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Mousavi Shafi ZS, Firouz ZM, Pirahmadi S. Gene expression analysis of Anopheles Meigen, 1818 (Diptera: Culicidae) innate immunity after Plasmodium Marchiafava & Celli, 1885 (Apicomplexa) infection: Toward developing new malaria control strategies. INFECTION, GENETICS AND EVOLUTION : JOURNAL OF MOLECULAR EPIDEMIOLOGY AND EVOLUTIONARY GENETICS IN INFECTIOUS DISEASES 2024; 123:105650. [PMID: 39089500 DOI: 10.1016/j.meegid.2024.105650] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2024] [Revised: 07/27/2024] [Accepted: 07/28/2024] [Indexed: 08/04/2024]
Abstract
Despite the critical role of the Anopheles innate immune system in defending against Plasmodium infection, there is still limited information about the key immune mechanisms in Anopheles. This review assesses recent findings on the expression characteristics of immune-related genes in Anopheles following exposure to Plasmodium. A literature review, unrestricted by publication date, was conducted to evaluate immune-related gene expression in different organs of Anopheles after Plasmodium infection. Mosquito immune responses in the midgut are essential for reducing parasite populations. Additionally, innate immune responses in the salivary glands and hemocytes circulating in the hemocoel play key roles in defense against the parasite. Transcriptomic analysis of the mosquito's innate immune response to Plasmodium infection provides valuable insights into key immune mechanisms in mosquito defense. A deeper understanding of immune mechanisms in different organs of Anopheles following Plasmodium infection will aid in discovering critical targets for designing novel control strategies.
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Affiliation(s)
- Zahra Sadat Mousavi Shafi
- Malaria and Vector Research Group (MVRG), Biotechnology Research Center (BRC), Pasteur Institute of Iran, Tehran, Iran
| | - Zeinab Mohammadi Firouz
- Malaria and Vector Research Group (MVRG), Biotechnology Research Center (BRC), Pasteur Institute of Iran, Tehran, Iran
| | - Sakineh Pirahmadi
- Malaria and Vector Research Group (MVRG), Biotechnology Research Center (BRC), Pasteur Institute of Iran, Tehran, Iran.
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Winter AK, Moss WJ. Possible Paths to Measles Eradication: Conceptual Frameworks, Strategies, and Tactics. Vaccines (Basel) 2024; 12:814. [PMID: 39066451 PMCID: PMC11281665 DOI: 10.3390/vaccines12070814] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2024] [Revised: 06/29/2024] [Accepted: 07/04/2024] [Indexed: 07/28/2024] Open
Abstract
Measles elimination refers to the interruption of measles virus transmission in a defined geographic area (e.g., country or region) for 12 months or more, and measles eradication refers to the global interruption of measles virus transmission. Measles eradication was first discussed and debated in the late 1960's shortly after the licensure of measles vaccines. Most experts agree that measles meets criteria for disease eradication, but progress toward national and regional measles elimination has slowed. Several paths to measles eradication can be described, including an incremental path through country-wide and regional measles elimination and phased paths through endgame scenarios and strategies. Infectious disease dynamic modeling can help inform measles elimination and eradication strategies, and all paths would be greatly facilitated by innovative technologies such as microarray patches to improve vaccine access and demand, point-of-contact diagnostic tests to facilitate outbreak responses, and point-of-contact IgG tests to identify susceptible populations. A pragmatic approach to measles eradication would identify and realize the necessary preconditions and clearly articulate various endgame scenarios and strategies to achieve measles eradication with an intensified and coordinated global effort in a specified timeframe, i.e., to "go big and go fast". To encourage and promote deliberation among a broad array of stakeholders, we provide a brief historical background and key considerations for setting a measles eradication goal.
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Affiliation(s)
- Amy K. Winter
- Department of Epidemiology and Biostatistics, College of Public Health, University of Georgia, Athens, GA 30602, USA;
| | - William J. Moss
- International Vaccine Access Center, Department of International Health, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD 21205, USA
- Department of Epidemiology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD 21205, USA
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Apeagyei AE, Patel NK, Cogswell I, O'Rourke K, Tsakalos G, Dieleman J. Examining geographical inequalities for malaria outcomes and spending on malaria in 40 malaria-endemic countries, 2010-2020. Malar J 2024; 23:206. [PMID: 38982498 PMCID: PMC11234708 DOI: 10.1186/s12936-024-05028-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Accepted: 06/26/2024] [Indexed: 07/11/2024] Open
Abstract
BACKGROUND While substantial gains have been made in the fight against malaria over the past 20 years, malaria morbidity and mortality are marked by inequality. The equitable elimination of malaria within countries will be determined in part by greater spending on malaria interventions, and how those investments are allocated. This study aims to identify potential drivers of malaria outcome inequality and to demonstrate how spending through different mechanisms might lead to greater health equity. METHODS Using the Gini index, subnational estimates of malaria incidence and mortality rates from 2010 to 2020 were used to quantify the degree of inequality in malaria burden within countries with incidence rates above 5000 cases per 100,000 people in 2020. Estimates of Gini indices represent within-country distributions of disease burden, with high values corresponding to inequitable distributions of malaria burden within a country. Time series analyses were used to quantify associations of malaria inequality with malaria spending, controlling for country socioeconomic and population characteristics. RESULTS Between 2010 and 2020, varying levels of inequality in malaria burden within malaria-endemic countries was found. In 2020, values of the Gini index ranged from 0.06 to 0.73 for incidence, 0.07 to 0.73 for mortality, and 0.00 to 0.36 for case fatality. Greater total malaria spending, spending on health systems strengthening for malaria, healthcare access and quality, and national malaria incidence were associated with reductions in malaria outcomes inequality within countries. In addition, government expenditure on malaria, aggregated government and donor spending on treatment, and maternal educational attainment were also associated with changes in malaria outcome inequality among countries with the greatest malaria burden. CONCLUSIONS The findings from this study suggest that prioritizing health systems strengthening in malaria spending and malaria spending in general especially from governments will help to reduce inequality of the malaria burden within countries. Given heterogeneity in outcomes in countries currently fighting to control malaria, and the challenges in increasing both domestic and international funding allocated to control and eliminate malaria, the efficient targeting of limited resources is critical to attain global malaria eradication goals.
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Affiliation(s)
- Angela E Apeagyei
- Institute for Health Metrics and Evaluation, 3980 15th Ave NE, Seattle, WA, 98195, USA.
| | - Nishali K Patel
- Institute for Health Metrics and Evaluation, 3980 15th Ave NE, Seattle, WA, 98195, USA
| | - Ian Cogswell
- Institute for Health Metrics and Evaluation, 3980 15th Ave NE, Seattle, WA, 98195, USA
| | - Kevin O'Rourke
- Institute for Health Metrics and Evaluation, 3980 15th Ave NE, Seattle, WA, 98195, USA
| | - Golsum Tsakalos
- Institute for Health Metrics and Evaluation, 3980 15th Ave NE, Seattle, WA, 98195, USA
| | - Joseph Dieleman
- Institute for Health Metrics and Evaluation, 3980 15th Ave NE, Seattle, WA, 98195, USA
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Kanga S, Roy P, Singh SK, Meraj G, Kumar P, Debnath J. Delineating dengue risk zones in Jaipur: An interdisciplinary approach to inform public health strategies. RISK ANALYSIS : AN OFFICIAL PUBLICATION OF THE SOCIETY FOR RISK ANALYSIS 2024. [PMID: 38987233 DOI: 10.1111/risa.15102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2023] [Revised: 06/05/2024] [Accepted: 06/16/2024] [Indexed: 07/12/2024]
Abstract
Dengue fever (DF) is a pervasive public health concern in tropical climates, with densely populated regions, such as India, disproportionately affected. Addressing this issue requires a multifaceted understanding of the environmental and sociocultural factors that contribute to the risk of dengue infection. This study aimed to identify high-risk zones for DF in Jaipur, Rajasthan, India, by integrating physical, demographic, and epidemiological data in a comprehensive risk analysis framework. We investigated environmental variables, such as soil type and plant cover, to characterize the potential habitats of Aedes aegypti, the primary dengue vector. Concurrently, demographic metrics were evaluated to assess the population's susceptibility to dengue outbreaks. High-risk areas were systematically identified through a comparative analysis that integrated population density and incidence rates per ward. The results revealed a significant correlation between high population density and an increased risk of dengue, predominantly facilitated by vertical transmission. Spatially, these high-risk zones are concentrated in the northern and southern sectors of Jaipur, with the northern and southwestern wards exhibiting the most acute risk profiles. This study underscores the importance of targeted public health interventions and vaccination campaigns in vulnerable areas. It further lays the groundwork for future research to evaluate the effectiveness of such interventions, thereby contributing to the development of robust evidence-based strategies for dengue risk mitigation.
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Affiliation(s)
- Shruti Kanga
- Department of Geography, School of Environment and Earth Sciences, Central University of Punjab, Bathinda, Punjab, India
| | - Priyanka Roy
- Centre for Climate Change and Water Research, Suresh Gyan Vihar University, Jaipur, Rajasthan, India
| | - Suraj Kumar Singh
- Centre for Sustainable Development, Suresh Gyan Vihar University, Jaipur, Rajasthan, India
| | - Gowhar Meraj
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - Pankaj Kumar
- Institute for Global Environmental Strategies, Hayama, Japan
| | - Jatan Debnath
- Department of Geography, Gauhati University, Jalukbari, Assam, India
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Benjamin-Chung J, Li H, Nguyen A, Barratt Heitmann G, Bennett A, Ntuku H, Prach LM, Tambo M, Wu L, Drakeley C, Gosling R, Mumbengegwi D, Kleinschmidt I, Smith JL, Hubbard A, van der Laan M, Hsiang MS. Extension of efficacy range for targeted malaria-elimination interventions due to spillover effects. Nat Med 2024:10.1038/s41591-024-03134-z. [PMID: 38965434 DOI: 10.1038/s41591-024-03134-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Accepted: 06/13/2024] [Indexed: 07/06/2024]
Abstract
Malaria-elimination interventions aim to extinguish hotspots and prevent transmission to nearby areas. Here, we re-analyzed a cluster-randomized trial of reactive, focal interventions (chemoprevention using artemether-lumefantrine and/or indoor residual spraying with pirimiphos-methyl) delivered within 500 m of confirmed malaria index cases in Namibia to measure direct effects (among intervention recipients within 500 m) and spillover effects (among non-intervention recipients within 3 km) on incidence, prevalence and seroprevalence. There was no or weak evidence of direct effects, but the sample size of intervention recipients was small, limiting statistical power. There was the strongest evidence of spillover effects of combined chemoprevention and indoor residual spraying. Among non-recipients within 1 km of index cases, the combined intervention reduced malaria incidence by 43% (95% confidence interval, 20-59%). In analyses among non-recipients within 3 km of interventions, the combined intervention reduced infection prevalence by 79% (6-95%) and seroprevalence, which captures recent infections and has higher statistical power, by 34% (20-45%). Accounting for spillover effects increased the cost-effectiveness of the combined intervention by 42%. Targeting hotspots with combined chemoprevention and vector-control interventions can indirectly benefit non-recipients up to 3 km away.
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Affiliation(s)
- Jade Benjamin-Chung
- Department of Epidemiology and Population Health, Stanford University, Stanford, CA, USA.
- Chan Zuckerberg Biohub, San Francisco, CA, USA.
| | - Haodong Li
- Division of Biostatistics, University of California, Berkeley, Berkeley, CA, USA
| | - Anna Nguyen
- Department of Epidemiology and Population Health, Stanford University, Stanford, CA, USA
| | | | - Adam Bennett
- Malaria Elimination Initiative, Global Health Group, University of California, San Francisco, San Francisco, CA, USA
- PATH, Seattle, WA, USA
| | - Henry Ntuku
- Malaria Elimination Initiative, Global Health Group, University of California, San Francisco, San Francisco, CA, USA
| | - Lisa M Prach
- Malaria Elimination Initiative, Global Health Group, University of California, San Francisco, San Francisco, CA, USA
| | - Munyaradzi Tambo
- Multidisciplinary Research Centre, University of Namibia, Windhoek, Namibia
| | - Lindsey Wu
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, UK
| | - Chris Drakeley
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, UK
| | - Roly Gosling
- Malaria Elimination Initiative, Global Health Group, University of California, San Francisco, San Francisco, CA, USA
- Department of Disease Control, London School of Hygiene and Tropical Medicine, London, UK
| | | | - Immo Kleinschmidt
- MRC International Statistics and Epidemiology Group, Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, UK
- Wits Research Institute for Malaria, Wits/SAMRC Collaborating Centre for Multi-Disciplinary Research on Malaria, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
- Southern African Development Community Malaria Elimination Eight Secretariat, Windhoek, Namibia
| | - Jennifer L Smith
- Malaria Elimination Initiative, Global Health Group, University of California, San Francisco, San Francisco, CA, USA
- Department of Epidemiology and Biostatistics, University of California, San Francisco, San Francisco, CA, USA
| | - Alan Hubbard
- Division of Biostatistics, University of California, Berkeley, Berkeley, CA, USA
| | - Mark van der Laan
- Division of Biostatistics, University of California, Berkeley, Berkeley, CA, USA
| | - Michelle S Hsiang
- Chan Zuckerberg Biohub, San Francisco, CA, USA
- Malaria Elimination Initiative, Global Health Group, University of California, San Francisco, San Francisco, CA, USA
- Department of Epidemiology and Biostatistics, University of California, San Francisco, San Francisco, CA, USA
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Mahamar A, Smit MJ, Sanogo K, Sinaba Y, Niambele SM, Sacko A, Dicko OM, Diallo M, Maguiraga SO, Sankaré Y, Keita S, Samake S, Dembele A, Lanke K, Ter Heine R, Bradley J, Dicko Y, Traore SF, Drakeley C, Dicko A, Bousema T, Stone W. Artemether-lumefantrine with or without single-dose primaquine and sulfadoxine-pyrimethamine plus amodiaquine with or without single-dose tafenoquine to reduce Plasmodium falciparum transmission: a phase 2, single-blind, randomised clinical trial in Ouelessebougou, Mali. THE LANCET. MICROBE 2024; 5:633-644. [PMID: 38705163 PMCID: PMC11217006 DOI: 10.1016/s2666-5247(24)00023-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2023] [Revised: 12/21/2023] [Accepted: 01/17/2024] [Indexed: 05/07/2024]
Abstract
BACKGROUND Artemether-lumefantrine is widely used for uncomplicated Plasmodium falciparum malaria; sulfadoxine-pyrimethamine plus amodiaquine is used for seasonal malaria chemoprevention. We aimed to determine the efficacy of artemether-lumefantrine with and without primaquine and sulfadoxine-pyrimethamine plus amodiaquine with and without tafenoquine for reducing gametocyte carriage and transmission to mosquitoes. METHODS In this phase 2, single-blind, randomised clinical trial conducted in Ouelessebougou, Mali, asymptomatic individuals aged 10-50 years with P falciparum gametocytaemia were recruited from the community and randomly assigned (1:1:1:1) to receive either artemether-lumefantrine, artemether-lumefantrine with a single dose of 0·25 mg/kg primaquine, sulfadoxine-pyrimethamine plus amodiaquine, or sulfadoxine-pyrimethamine plus amodiaquine with a single dose of 1·66 mg/kg tafenoquine. All trial staff other than the pharmacist were masked to group allocation. Participants were not masked to group allocation. Randomisation was done with a computer-generated randomisation list and concealed with sealed, opaque envelopes. The primary outcome was the median within-person percent change in mosquito infection rate in infectious individuals from baseline to day 2 (artemether-lumefantrine groups) or day 7 (sulfadoxine-pyrimethamine plus amodiaquine groups) after treatment, assessed by direct membrane feeding assay. All participants who received any trial drug were included in the safety analysis. This study is registered with ClinicalTrials.gov, NCT05081089. FINDINGS Between Oct 13 and Dec 16, 2021, 1290 individuals were screened and 80 were enrolled and randomly assigned to one of the four treatment groups (20 per group). The median age of participants was 13 (IQR 11-20); 37 (46%) of 80 participants were female and 43 (54%) were male. In individuals who were infectious before treatment, the median percentage reduction in mosquito infection rate 2 days after treatment was 100·0% (IQR 100·0-100·0; n=19; p=0·0011) with artemether-lumefantrine and 100·0% (100·0-100·0; n=19; p=0·0001) with artemether-lumefantrine with primaquine. Only two individuals who were infectious at baseline infected mosquitoes on day 2 after artemether-lumefantrine and none at day 5. By contrast, the median percentage reduction in mosquito infection rate 7 days after treatment was 63·6% (IQR 0·0-100·0; n=20; p=0·013) with sulfadoxine-pyrimethamine plus amodiaquine and 100% (100·0-100·0; n=19; p<0·0001) with sulfadoxine-pyrimethamine plus amodiaquine with tafenoquine. No grade 3-4 or serious adverse events occurred. INTERPRETATION These data support the effectiveness of artemether-lumefantrine alone for preventing nearly all mosquito infections. By contrast, there was considerable post-treatment transmission after sulfadoxine-pyrimethamine plus amodiaquine; therefore, the addition of a transmission-blocking drug might be beneficial in maximising its community impact. FUNDING Bill & Melinda Gates Foundation.
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Affiliation(s)
- Almahamoudou Mahamar
- Malaria Research and Training Centre, Faculty of Pharmacy and Faculty of Medicine and Dentistry, University of Sciences Techniques and Technologies of Bamako, Bamako, Mali.
| | - Merel J Smit
- Department of Medical Microbiology and Radboud Center for Infectious Diseases, Radboud University Medical Center, Nijmegen, Netherlands
| | - Koualy Sanogo
- Malaria Research and Training Centre, Faculty of Pharmacy and Faculty of Medicine and Dentistry, University of Sciences Techniques and Technologies of Bamako, Bamako, Mali
| | - Youssouf Sinaba
- Malaria Research and Training Centre, Faculty of Pharmacy and Faculty of Medicine and Dentistry, University of Sciences Techniques and Technologies of Bamako, Bamako, Mali
| | - Sidi M Niambele
- Malaria Research and Training Centre, Faculty of Pharmacy and Faculty of Medicine and Dentistry, University of Sciences Techniques and Technologies of Bamako, Bamako, Mali
| | - Adama Sacko
- Malaria Research and Training Centre, Faculty of Pharmacy and Faculty of Medicine and Dentistry, University of Sciences Techniques and Technologies of Bamako, Bamako, Mali
| | - Oumar M Dicko
- Malaria Research and Training Centre, Faculty of Pharmacy and Faculty of Medicine and Dentistry, University of Sciences Techniques and Technologies of Bamako, Bamako, Mali
| | - Makonon Diallo
- Malaria Research and Training Centre, Faculty of Pharmacy and Faculty of Medicine and Dentistry, University of Sciences Techniques and Technologies of Bamako, Bamako, Mali
| | - Seydina O Maguiraga
- Malaria Research and Training Centre, Faculty of Pharmacy and Faculty of Medicine and Dentistry, University of Sciences Techniques and Technologies of Bamako, Bamako, Mali
| | - Yaya Sankaré
- Malaria Research and Training Centre, Faculty of Pharmacy and Faculty of Medicine and Dentistry, University of Sciences Techniques and Technologies of Bamako, Bamako, Mali
| | - Sekouba Keita
- Malaria Research and Training Centre, Faculty of Pharmacy and Faculty of Medicine and Dentistry, University of Sciences Techniques and Technologies of Bamako, Bamako, Mali
| | - Siaka Samake
- Malaria Research and Training Centre, Faculty of Pharmacy and Faculty of Medicine and Dentistry, University of Sciences Techniques and Technologies of Bamako, Bamako, Mali
| | - Adama Dembele
- Malaria Research and Training Centre, Faculty of Pharmacy and Faculty of Medicine and Dentistry, University of Sciences Techniques and Technologies of Bamako, Bamako, Mali
| | - Kjerstin Lanke
- Department of Medical Microbiology and Radboud Center for Infectious Diseases, Radboud University Medical Center, Nijmegen, Netherlands
| | - Rob Ter Heine
- Department of Pharmacy and Radboud Center for Infectious Diseases, Radboud University Medical Center, Nijmegen, Netherlands
| | - John Bradley
- MRC International Statistics and Epidemiology Group, London School of Hygiene and Tropical Medicine, London, UK
| | - Yahia Dicko
- Malaria Research and Training Centre, Faculty of Pharmacy and Faculty of Medicine and Dentistry, University of Sciences Techniques and Technologies of Bamako, Bamako, Mali
| | - Sekou F Traore
- Malaria Research and Training Centre, Faculty of Pharmacy and Faculty of Medicine and Dentistry, University of Sciences Techniques and Technologies of Bamako, Bamako, Mali
| | - Chris Drakeley
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, UK
| | - Alassane Dicko
- Malaria Research and Training Centre, Faculty of Pharmacy and Faculty of Medicine and Dentistry, University of Sciences Techniques and Technologies of Bamako, Bamako, Mali
| | - Teun Bousema
- Department of Medical Microbiology and Radboud Center for Infectious Diseases, Radboud University Medical Center, Nijmegen, Netherlands
| | - Will Stone
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, UK
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Pian H, Wang H, Wang H, Li Z. Dual CRISPR/Cas13a Cascade Strand Displacement-Triggered Transcription for Point-of-Care Detection of Plasmodium in Asymptomatic Malaria. Anal Chem 2024; 96:7524-7531. [PMID: 38695755 DOI: 10.1021/acs.analchem.4c00230] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/15/2024]
Abstract
Asymptomatic infections of Plasmodium parasites are major obstacles to malaria control and elimination. A sensitive, specific, and user-friendly method is urgently needed for point-of-care (POC) Plasmodium diagnostics in asymptomatic malaria, especially in resource-limited settings. In this work, we present a POC method (termed Cas13a-SDT) based on the cascade sequence recognition and signal amplification of dual Cas13a trans-cleavage and strand displacement-triggered transcription (SDT). Cas13a-SDT not only achieves exceptional specificity in discriminating the target RNA from nontarget RNAs with any cross-interaction but also meets the sensitivity criterion set by the World Health Organization (WHO) for effective malaria detection. Remarkably, this novel method was successfully applied to screen malaria in asymptomatic infections from clinical samples. The proposed method provides a user-friendly and visually interpretable output mode while maintaining high accuracy and reliability comparable to RT-PCR. These excellent features demonstrate the significant potential of Cas13a-SDT for POC diagnosis of Plasmodium infections, laying a vital foundation for advancing malaria control and elimination efforts.
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Affiliation(s)
- Hongru Pian
- Beijing Key Laboratory for Bioengineering and Sensing Technology, School of Chemistry and Biological Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Hui Wang
- Beijing Key Laboratory for Bioengineering and Sensing Technology, School of Chemistry and Biological Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Honghong Wang
- Beijing Key Laboratory for Bioengineering and Sensing Technology, School of Chemistry and Biological Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Zhengping Li
- Beijing Key Laboratory for Bioengineering and Sensing Technology, School of Chemistry and Biological Engineering, University of Science and Technology Beijing, Beijing 100083, China
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Lyimo BM, Bakari C, Popkin-Hall ZR, Giesbrecht DJ, Seth MD, Pereus D, Shabani ZI, Moshi R, Boniface R, Mandara CI, Madebe R, Juliano JJ, Bailey JA, Ishengoma DS. Genetic polymorphism and evidence of signatures of selection in the Plasmodium falciparum circumsporozoite protein gene in Tanzanian regions with different malaria endemicity. Malar J 2024; 23:139. [PMID: 38720288 PMCID: PMC11080125 DOI: 10.1186/s12936-024-04974-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2024] [Accepted: 05/03/2024] [Indexed: 05/12/2024] Open
Abstract
BACKGROUND In 2021 and 2023, the World Health Organization approved RTS,S/AS01 and R21/Matrix M malaria vaccines, respectively, for routine immunization of children in African countries with moderate to high transmission. These vaccines are made of Plasmodium falciparum circumsporozoite protein (PfCSP), but polymorphisms in the gene raise concerns regarding strain-specific responses and the long-term efficacy of these vaccines. This study assessed the Pfcsp genetic diversity, population structure and signatures of selection among parasites from areas of different malaria transmission intensities in Mainland Tanzania, to generate baseline data before the introduction of the malaria vaccines in the country. METHODS The analysis involved 589 whole genome sequences generated by and as part of the MalariaGEN Community Project. The samples were collected between 2013 and January 2015 from five regions of Mainland Tanzania: Morogoro and Tanga (Muheza) (moderate transmission areas), and Kagera (Muleba), Lindi (Nachingwea), and Kigoma (Ujiji) (high transmission areas). Wright's inbreeding coefficient (Fws), Wright's fixation index (FST), principal component analysis, nucleotide diversity, and Tajima's D were used to assess within-host parasite diversity, population structure and natural selection. RESULTS Based on Fws (< 0.95), there was high polyclonality (ranging from 69.23% in Nachingwea to 56.9% in Muheza). No population structure was detected in the Pfcsp gene in the five regions (mean FST = 0.0068). The average nucleotide diversity (π), nucleotide differentiation (K) and haplotype diversity (Hd) in the five regions were 4.19, 0.973 and 0.0035, respectively. The C-terminal region of Pfcsp showed high nucleotide diversity at Th2R and Th3R regions. Positive values for the Tajima's D were observed in the Th2R and Th3R regions consistent with balancing selection. The Pfcsp C-terminal sequences revealed 50 different haplotypes (H_1 to H_50), with only 2% of sequences matching the 3D7 strain haplotype (H_50). Conversely, with the NF54 strain, the Pfcsp C-terminal sequences revealed 49 different haplotypes (H_1 to H_49), with only 0.4% of the sequences matching the NF54 strain (Hap_49). CONCLUSIONS The findings demonstrate high diversity of the Pfcsp gene with limited population differentiation. The Pfcsp gene showed positive Tajima's D values, consistent with balancing selection for variants within Th2R and Th3R regions. The study observed differences between the intended haplotypes incorporated into the design of RTS,S and R21 vaccines and those present in natural parasite populations. Therefore, additional research is warranted, incorporating other regions and more recent data to comprehensively assess trends in genetic diversity within this important gene. Such insights will inform the choice of alleles to be included in the future vaccines.
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Affiliation(s)
- Beatus M Lyimo
- National Institute for Medical Research, Dar es Salaam, Tanzania.
- Nelson Mandela African Institution of Science and Technology, Arusha, Tanzania.
| | - Catherine Bakari
- National Institute for Medical Research, Dar es Salaam, Tanzania
| | | | | | - Misago D Seth
- National Institute for Medical Research, Dar es Salaam, Tanzania
| | - Dativa Pereus
- National Institute for Medical Research, Dar es Salaam, Tanzania
- Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania
| | - Zulfa I Shabani
- Dar Es Salaam University College of Education, University of Dar es Salaam, Dar es Salaam, Tanzania
| | - Ramadhan Moshi
- National Institute for Medical Research, Dar es Salaam, Tanzania
| | - Ruth Boniface
- National Institute for Medical Research, Dar es Salaam, Tanzania
- Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania
| | - Celine I Mandara
- National Institute for Medical Research, Dar es Salaam, Tanzania
| | - Rashid Madebe
- National Institute for Medical Research, Dar es Salaam, Tanzania
| | | | | | - Deus S Ishengoma
- National Institute for Medical Research, Dar es Salaam, Tanzania
- Harvard T.H Chan School of Public Health, Boston, MA, USA
- Faculty of Pharmaceutical Sciences, Monash University, Melbourne, Australia
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Dionne JA, Anchang-Kimbi J, Hao J, Long D, Apinjoh T, Tih P, Mbah R, Ngah EN, Juliano JJ, Kahn M, Bruxvoort K, Van Der Pol B, Tita ATN, Marrazzo J, Achidi E. Trimethoprim-Sulfamethoxazole Plus Azithromycin to Prevent Malaria and Sexually Transmitted Infections in Pregnant Women With HIV (PREMISE): A Randomized, Double-Masked, Placebo-Controlled, Phase IIB Clinical Trial. Open Forum Infect Dis 2024; 11:ofae274. [PMID: 38807754 PMCID: PMC11130525 DOI: 10.1093/ofid/ofae274] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2024] [Accepted: 05/06/2024] [Indexed: 05/30/2024] Open
Abstract
Background This trial tested the effectiveness of a novel regimen to prevent malaria and sexually transmitted infections (STIs) among pregnant women with HIV in Cameroon. Our hypothesis was that the addition of azithromycin (AZ) to standard daily trimethoprim-sulfamethoxazole (TMP-SMX) prophylaxis would reduce malaria and STI infection rates at delivery. Methods Pregnant women with HIV at gestational age <28 weeks were randomized to adjunctive monthly oral AZ 1 g daily or placebo for 3 days and both groups received daily standard oral TMP-SMX through delivery. Primary outcomes were (1) positive peripheral malaria infection by microscopy or polymerase chain reaction and (2) composite bacterial genital STI (Chlamydia trachomatis, Neisseria gonorrhoeae, or syphilis) at delivery. Relative risk and 95% confidence intervals were estimated using 2 × 2 tables with significance as P < .05. Results Pregnant women with HIV (n = 308) were enrolled between March 2018 and August 2020: 155 women were randomized to TMP-SMX-AZ and 153 women to TMP-SMX-placebo. Groups were similar at baseline and loss to follow up was 3.2%. There was no difference in the proportion with malaria (16.3% in TMP-SMX-AZ vs 13.2% in TMP-SMX; relative risk, 1.24 [95% confidence interval, .71-2.16]) or STI at delivery (4.2% in TMP-SMX-AZ vs 5.8% in TMP-SMX; relative risk, 0.72 [95% confidence interval, .26-2.03]). Adverse birth outcomes were not significantly different, albeit lower in the TMP-SMX-AZ arm (preterm delivery 6.7% vs 10.7% [P = .3]; low birthweight 3.4% vs 5.4% [P = .6]). Conclusions The addition of monthly azithromycin to daily TMP-SMX prophylaxis in pregnant women living with HIV in Cameroon did not reduce the risk of malaria or bacterial STI at delivery.
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Affiliation(s)
- Jodie A Dionne
- Department of Medicine, Division of Infectious Diseases, University of Alabama at Birmingham, Birmingham, Alabama, USA
- Center for Women's Reproductive Health, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | | | - Jiaying Hao
- Departments of Biostatistics and Epidemiology, School of Public Health, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Dustin Long
- Departments of Biostatistics and Epidemiology, School of Public Health, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Tobias Apinjoh
- Department of Parasitology and Immunology, University of Buea, Buea, Cameroon
| | - Pius Tih
- Cameroon Baptist Convention Health Services, Cameroon Health Initiative at UAB, Bamenda, Cameroon
| | - Rahel Mbah
- Cameroon Baptist Convention Health Services, Cameroon Health Initiative at UAB, Bamenda, Cameroon
| | - Edward Ndze Ngah
- Cameroon Baptist Convention Health Services, Cameroon Health Initiative at UAB, Bamenda, Cameroon
| | - Jonathan J Juliano
- Department of Medicine, Division of Infectious Diseases, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Mauricio Kahn
- Department of Medicine, Division of Infectious Diseases, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Katia Bruxvoort
- Department of Medicine, Division of Infectious Diseases, University of Alabama at Birmingham, Birmingham, Alabama, USA
- Departments of Biostatistics and Epidemiology, School of Public Health, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Barbara Van Der Pol
- Department of Medicine, Division of Infectious Diseases, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Alan T N Tita
- Center for Women's Reproductive Health, University of Alabama at Birmingham, Birmingham, Alabama, USA
- Department of Obstetrics and Gynecology, Division of Maternal-Fetal Medicine, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Jeanne Marrazzo
- Department of Medicine, Division of Infectious Diseases, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Eric Achidi
- Department of Parasitology and Immunology, University of Buea, Buea, Cameroon
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Obeagu EI. Role of cytokines in immunomodulation during malaria clearance. Ann Med Surg (Lond) 2024; 86:2873-2882. [PMID: 38694310 PMCID: PMC11060309 DOI: 10.1097/ms9.0000000000002019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2023] [Accepted: 03/22/2024] [Indexed: 05/04/2024] Open
Abstract
Malaria remains a significant global health challenge, demanding a deeper understanding of host immune responses for effective clearance of the parasitic infection. Cytokines, as crucial mediators of the immune system, orchestrate a complex interplay during the various stages of malaria infection. Throughout the course of the disease, an intricate balance of pro-inflammatory and anti-inflammatory cytokines dictate the immune response's outcome, influencing parasitic clearance and disease severity. During the initial stages, interleukins such as interleukin-12 (IL-12), interferon-gamma (IFN-γ), and tumour necrosis factor-alpha (TNF-α) play pivotal roles in activating innate immune cells, initiating the anti-parasitic response. Simultaneously, regulatory cytokines like interleukin-10 (IL-10) and transforming growth factor-beta (TGF-β) modulate this immune activation, preventing excessive inflammation and tissue damage. As the infection progresses, a delicate shift occurs, characterized by a transition to adaptive immunity, guided by cytokines like interleukin-4 (IL-4), interleukin-5 (IL-5), and interleukin-13 (IL-13), promoting antibody production and T-cell responses. Notably, the resolution of malaria infection crucially relies on a fine-tuned balance of cytokine networks. Dysregulation or imbalances in these mediators often result in immune hyperactivation, contributing to severe manifestations and prolonged infection. Understanding the multi-faceted roles of cytokines in malaria clearance offers promising avenues for therapeutic interventions. Targeting cytokine pathways to restore immune equilibrium or bolster protective responses could potentially enhance treatment strategies and vaccine development. In conclusion, the pivotal role of cytokines in immunomodulation during malaria clearance underscores their significance as potential targets for therapeutic interventions, offering promising prospects in the global fight against this infectious disease.
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11
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Assefa A, Wamae K, Hennelly CM, Ngasala B, Muller M, Kalonji A, Phanzu F, Cunningham CH, Lin JT, Parr JB. Detection of P. malariae using a new rapid isothermal amplification lateral flow assay. Malar J 2024; 23:104. [PMID: 38609964 PMCID: PMC11015614 DOI: 10.1186/s12936-024-04928-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Accepted: 04/03/2024] [Indexed: 04/14/2024] Open
Abstract
BACKGROUND While Plasmodium falciparum and Plasmodium vivax cause the majority of malaria cases and deaths, infection by Plasmodium malariae and other Plasmodium species also causes morbidity and mortality. Current understanding of these infections is limited in part by existing point-of-care diagnostics that fail to differentiate them and have poor sensitivity for low-density infections. Accurate diagnosis currently requires molecular assays performed in well-resourced laboratories. This report describes the development of a P. malariae diagnostic assay that uses rapid, isothermal recombinase polymerase amplification (RPA) and lateral-flow-strip detection. METHODS Multiple combinations of custom RPA primers and probes were designed using publicly available P. malariae genomic sequences, and by modifying published primer sets. Based on manufacturer RPA reaction conditions (TwistDx nfo kit), an isothermal assay was optimized targeting the multicopy P. malariae 18S rRNA gene with 39 °C incubation and 30-min run time. RPA product was visualized using lateral strips (FAM-labeled, biotinylated amplicon detected by a sandwich immunoassay, visualized using gold nanoparticles). Analytical sensitivity was evaluated using 18S rRNA plasmid DNA, and clinical sensitivity determined using qPCR-confirmed samples collected from Tanzania, Ethiopia, and the Democratic Republic of the Congo. RESULTS Using 18S rRNA plasmid DNA, the assay demonstrates a detection limit of 10 copies/µL (~ 1.7 genome equivalents) and 100% analytical specificity. Testing in field samples showed 95% clinical sensitivity and 88% specificity compared to qPCR. Total assay time was less than 40 min. CONCLUSION Combined with simplified DNA extraction methods, the assay has potential for future field-deployable, point-of-care use to detect P. malariae infection, which remains largely undiagnosed but a neglected cause of chronic malaria. The assay provides a rapid, simple readout on a lateral flow strip without the need for expensive laboratory equipment.
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Affiliation(s)
- Ashenafi Assefa
- Ethiopian Public Health Institute, Addis Ababa, Ethiopia.
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, NC, USA.
| | - Kevin Wamae
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, NC, USA
| | - Christopher M Hennelly
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, NC, USA
| | - Billy Ngasala
- Department of Parasitology and Medical Entomology, Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania
| | - Meredith Muller
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, NC, USA
| | | | | | - Clark H Cunningham
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, NC, USA
| | - Jessica T Lin
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, NC, USA
| | - Jonathan B Parr
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, NC, USA.
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12
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Hossain MS, Ahmed TS, Haque MA, Chowdhury MAB, Uddin MJ. Prevalence of unqualified sources of antimalarial drug prescription for children under the age of five: A study in 19 low- and middle-income countries. PLoS One 2024; 19:e0300347. [PMID: 38512855 PMCID: PMC10956821 DOI: 10.1371/journal.pone.0300347] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2023] [Accepted: 02/26/2024] [Indexed: 03/23/2024] Open
Abstract
BACKGROUND Antimalarial drug resistance poses a severe danger to global health. In Low- and Middle-Income Countries (LMICs), there is a lack of reliable information on antimalarial prescriptions for recent malarial fever in children under five. Our study aims to determine the prevalence of unqualified sources of antimalarial drug prescription for children under the age of five in 19 low- and middle-income countries. METHODS We performed a cross-sectional study of the Malaria Indicator Survey (MIS) datasets (n = 106265) across 19 LMICs. The recent MIS datasets were used, and the study only included children under five who had taken an antimalarial drug for a recent malarial fever. The outcome variable was classified into two distinct categories: those who had taken antimalarial drugs for malarial fever from qualified sources and those who did not. FINDINGS Among LMICs, we found that 87.1% of children under five received an antimalarial prescription from unqualified sources who had recently experienced malarial fever. In several LMICs (Tanzania, Nigeria, and Ghana), a substantial portion of recent antimalarial prescriptions for malaria was taken from unqualified sources (about 60%). Some LMICs (Guinea (31.8%), Mali (31.3%), Nigeria (20.4%), Kenya (2.6%), and Senegal (2.7%)) had low rates of antimalarial drug consumption even though children under five received a high percentage of antimalarial prescriptions from qualified sources for a recent malarial fever. Living in rural areas, having mothers with higher education, and having parents with more wealth were frequently taken antimalarial from qualified sources for recent malarial fever in children under five across the LMICs. INTERPRETATION The study draws attention to the importance of national and local level preventative strategies across the LMICs to restrict antimalarial drug consumption. This is because antimalarial prescriptions from unqualified sources for recent malarial fever in children under five were shockingly high in most LMICs and had high rates of unqualified prescriptions in certain other LMICs.
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Affiliation(s)
- Md Sabbir Hossain
- Biostatistics, Epidemiology and Public Health Research Team, Department of Statistics, Shahjalal University of Science and Technology, Sylhet, Bangladesh
| | - Talha Sheikh Ahmed
- Department of Geography and Environment, Shahjalal University of Science and Technology, Sylhet, Bangladesh
| | - Mohammad Anamul Haque
- Biostatistics, Epidemiology and Public Health Research Team, Department of Statistics, Shahjalal University of Science and Technology, Sylhet, Bangladesh
| | - Muhammad Abdul Baker Chowdhury
- Biostatistics, Epidemiology and Public Health Research Team, Department of Statistics, Shahjalal University of Science and Technology, Sylhet, Bangladesh
| | - Md Jamal Uddin
- Biostatistics, Epidemiology and Public Health Research Team, Department of Statistics, Shahjalal University of Science and Technology, Sylhet, Bangladesh
- Department of General Educational and Development, Daffodil International University, Dhaka, Bangladesh
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13
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Gallalee S, Zarlinda I, Silaen MG, Cotter C, Cueto C, Elyazar IRF, Jacobson JO, Gosling R, Hsiang MS, Bennett A, Coutrier FN, Smith JL. Forest-goers as a heterogeneous population at high-risk for malaria: a case-control study in Aceh Province, Indonesia. Malar J 2024; 23:37. [PMID: 38291392 PMCID: PMC10826189 DOI: 10.1186/s12936-024-04856-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Accepted: 01/20/2024] [Indexed: 02/01/2024] Open
Abstract
BACKGROUND A major challenge to malaria elimination is identifying and targeting populations that are harbouring residual infections and contributing to persistent transmission. In many near-elimination settings in Southeast Asia, it is known that forest-goers are at higher risk for malaria infection, but detailed information on their behaviours and exposures is not available. METHODS In Aceh Province, Indonesia, a near-elimination setting where a growing proportion of malaria is due to Plasmodium knowlesi, a case-control study was conducted to identify risk factors for symptomatic malaria, characteristics of forest-goers, and key intervention points. From April 2017 to September 2018, cases and controls were recruited and enrolled in a 1:3 ratio. Cases had confirmed malaria infection by rapid diagnostic test or microscopy detected at a health facility (HF). Gender-matched controls were recruited from passive case detection among individuals with suspected malaria who tested negative at a health facility (HF controls), and community-matched controls were recruited among those testing negative during active case detection. Multivariable logistic regression (unconditional for HF controls and conditional for community controls) was used to identify risk factors for symptomatic malaria infection. RESULTS There were 45 cases, of which 27 were P. knowlesi, 17 were Plasmodium vivax, and one was not determined. For controls, 509 and 599 participants were recruited from health facilities and the community, respectively. Forest exposures were associated with high odds of malaria; in particular, working and sleeping in the forest (HF controls: adjusted odds ratio (aOR) 21.66, 95% CI 5.09-92.26; community controls: aOR 16.78, 95% CI 2.19-128.7) and having a second residence in the forest (aOR 6.29, 95% CI 2.29-17.31 and 13.53, 95% CI 2.10-87.12). Male forest-goers were a diverse population employed in a variety of occupations including logging, farming, and mining, sleeping in settings, such as huts, tents, and barracks, and working in a wide range of group sizes. Reported use of protective measures, such as nets, hammock nets, mosquito coils, and repellents was low among forest-goers and interventions at forest residences were absent. CONCLUSIONS Second residences in the forest and gaps in use of protective measures point to key malaria interventions to improve coverage in forest-going populations at risk for P. knowlesi and P. vivax in Aceh, Indonesia. Intensified strategies tailored to specific sub-populations will be essential to achieve elimination.
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Affiliation(s)
- Sarah Gallalee
- Malaria Elimination Initiative, Institute for Global Health Sciences, University of California San Francisco, San Francisco, CA, USA.
| | - Iska Zarlinda
- Malaria Pathogenesis Unit, Eijkman Institute for Molecular Biology, Jakarta, Indonesia
| | - Martha G Silaen
- Malaria Pathogenesis Unit, Eijkman Institute for Molecular Biology, Jakarta, Indonesia
| | - Chris Cotter
- Malaria Elimination Initiative, Institute for Global Health Sciences, University of California San Francisco, San Francisco, CA, USA
- Department of Women's and Children's Health, Uppsala University, Uppsala, Sweden
| | - Carmen Cueto
- Malaria Elimination Initiative, Institute for Global Health Sciences, University of California San Francisco, San Francisco, CA, USA
| | - Iqbal R F Elyazar
- Eijkman-Oxford Clinical Research Unit, Eijkman Institute for Molecular Biology, Jakarta, Indonesia
| | - Jerry O Jacobson
- Malaria Elimination Initiative, Institute for Global Health Sciences, University of California San Francisco, San Francisco, CA, USA
| | - Roly Gosling
- Malaria Elimination Initiative, Institute for Global Health Sciences, University of California San Francisco, San Francisco, CA, USA
- Department of Disease Control, London School of Hygiene and Tropical Medicine, London, UK
| | - Michelle S Hsiang
- Malaria Elimination Initiative, Institute for Global Health Sciences, University of California San Francisco, San Francisco, CA, USA
- Department of Epidemiology and Biostatistics, University of California San Francisco, San Francisco, CA, USA
- Department of Pediatrics, University of California San Francisco, Benioff Children's Hospital, San Francisco, CA, USA
| | - Adam Bennett
- Malaria Elimination Initiative, Institute for Global Health Sciences, University of California San Francisco, San Francisco, CA, USA
- Department of Epidemiology and Biostatistics, University of California San Francisco, San Francisco, CA, USA
| | - Farah N Coutrier
- Malaria Pathogenesis Unit, Eijkman Institute for Molecular Biology, Jakarta, Indonesia
- Eijkman Research Center for Molecular Biology, National Research and Innovation Agency (BRIN), Jakarta, Indonesia
| | - Jennifer L Smith
- Malaria Elimination Initiative, Institute for Global Health Sciences, University of California San Francisco, San Francisco, CA, USA
- Department of Epidemiology and Biostatistics, University of California San Francisco, San Francisco, CA, USA
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Lyimo BM, Bakari C, Popkin-Hall ZR, Giesbrecht DJ, Seth MD, Pereus D, Moshi R, Boniface R, Mandara CI, Madebe R, Juliano JJ, Bailey JA, Ishengoma DS. Genetic polymorphism and evidence of signatures of selection in the Plasmodium falciparum circumsporozoite protein gene in Tanzanian regions with different malaria endemicity. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2024:2024.01.23.24301587. [PMID: 38343796 PMCID: PMC10854334 DOI: 10.1101/2024.01.23.24301587] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/17/2024]
Abstract
Background In 2021 and 2023, the World Health Organization approved RTS, S/AS01 and R21/Matrix M malaria vaccines, respectively, for routine immunization of children in African countries with moderate to high transmission. These vaccines are made of Plasmodium falciparum circumsporozoite protein (Pfcsp) but polymorphisms in this gene raises concerns regarding strain-specific responses and the long-term efficacy of these vaccines. This study assessed the Pfcsp genetic diversity, population structure and signatures of selection among parasites from areas of different malaria transmission in mainland Tanzania, to generate baseline data before the introduction of the malaria vaccines in the country. Methods The analysis involved 589 whole genome sequences generated by and as part of the MalariaGEN Community Project. The samples were collected between 2013 and January 2015 from five regions of mainland Tanzania: Morogoro and Tanga (Muheza) (moderate transmission areas), and Kagera (Muleba), Lindi (Nachingwea), and Kigoma (Ujiji) (high transmission areas). Wright's inbreeding coefficient (Fws), Wright's fixation index (FST), principal component analysis, nucleotide diversity, and Tajima's D were used to assess within-host parasite diversity, population structure and natural selection. Results Based on Fws (< 0.95), there was high polyclonality (ranged from 69.23% in Nachingwea to 56.9% in Muheza). No population structure was detected in the Pfcsp gene in the five regions (mean FST= 0.0068). The average nucleotide diversity (π), nucleotide differentiation (K) and haplotype diversity (Hd) in the five regions were 4.19, 0.973 and 0.0035, respectively. The C-terminal region of Pfcsp showed high nucleotide diversity at Th2R and Th3R regions. Positive values for the Tajima's D were observed in the Th2R and Th3R regions consistent with balancing selection. The Pfcsp C-terminal sequences had 50 different haplotypes (H_1 to H_50) and only 2% of sequences matched the 3D7 strain haplotype (H_50). Conclusions The findings demonstrate high diversity of the Pfcsp gene with limited population differentiation. The Pfcsp gene showed positive Tajima's D values for parasite populations, consistent with balancing selection for variants within Th2R and Th3R regions. This data is consistent with other studies conducted across Africa and worldwide, which demonstrate low 3D7 haplotypes and little population structure. Therefore, additional research is warranted, incorporating other regions and more recent data to comprehensively assess trends in genetic diversity within this important gene. Such insights will inform the choice of alleles to be included in the future vaccines.
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Affiliation(s)
- Beatus M. Lyimo
- National Institute for Medical Research, Dar es Salaam, Tanzania
- Nelson Mandela African Institution of Science and Technology, Arusha, Tanzania
| | - Catherine Bakari
- National Institute for Medical Research, Dar es Salaam, Tanzania
| | | | | | - Misago D. Seth
- National Institute for Medical Research, Dar es Salaam, Tanzania
| | - Dativa Pereus
- National Institute for Medical Research, Dar es Salaam, Tanzania
- Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania
| | - Ramadhan Moshi
- National Institute for Medical Research, Dar es Salaam, Tanzania
| | - Ruth Boniface
- National Institute for Medical Research, Dar es Salaam, Tanzania
- Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania
| | | | - Rashid Madebe
- National Institute for Medical Research, Dar es Salaam, Tanzania
| | | | | | - Deus S. Ishengoma
- National Institute for Medical Research, Dar es Salaam, Tanzania
- Harvard T.H Chan School of Public Health, Boston, MA, USA
- Faculty of Pharmaceutical Sciences, Monash University, Melbourne, Australia
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Rajvanshi H, Singh MP, Bharti PK, Sahu RS, Jayswar H, Govil PJ, Anvikar A, Chan XX, Chebbi A, Das S, Lal AA. Science of malaria elimination: using knowledge of bottlenecks and enablers from the Malaria Elimination Demonstration Project in Central India for eliminating malaria in the Asia Pacific region. Front Public Health 2024; 11:1303095. [PMID: 38303961 PMCID: PMC10830794 DOI: 10.3389/fpubh.2023.1303095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Accepted: 11/27/2023] [Indexed: 02/03/2024] Open
Abstract
Malaria poses a major public health challenge in the Asia Pacific. Malaria Elimination Demonstration Project was conducted as a public-private partnership initiative in Mandla between State government, ICMR, and FDEC India. The project employed controls for efficient operational and management decisions. IEC campaigns found crucial in schools and communities. Capacity building of local workers emphasized for better diagnosis and treatment. SOCH mobile app launched for complete digitalization. Better supervision for Indoor Residual Sprays and optimized Long Lasting Insecticidal Nets distribution. Significant malaria cases reduction in Mandla. Insights from MEDP crucial for malaria elimination strategies in other endemic regions of the Asia Pacific.
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Affiliation(s)
- Harsh Rajvanshi
- Asia Pacific Leaders' Malaria Alliance, Singapore, Singapore
| | - Mrigendra P. Singh
- Foundation for Disease Elimination and Control of India, Mumbai, Maharashtra, India
| | - Praveen K. Bharti
- Indian Council of Medical Research – National Institute of Malaria Research, New Delhi, India
| | | | - Himanshu Jayswar
- Directorate of Health Services, Government of Madhya Pradesh, Bhopal, India
| | - Pallavi Jain Govil
- Department of Tribal Welfare, Government of Madhya Pradesh, Bhopal, India
| | - Anup Anvikar
- Indian Council of Medical Research – National Institute of Malaria Research, New Delhi, India
| | | | - Amita Chebbi
- Asia Pacific Leaders' Malaria Alliance, Singapore, Singapore
| | - Sarthak Das
- Asia Pacific Leaders' Malaria Alliance, Singapore, Singapore
| | - Altaf A. Lal
- Foundation for Disease Elimination and Control of India, Mumbai, Maharashtra, India
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Agumba S, Moshi V, Muchoki M, Omondi S, Kosgei J, Walker ED, Abong'o B, Achee N, Grieco J, Ochomo E. Experimental hut and field evaluation of a metofluthrin-based spatial repellent against pyrethroid-resistant Anopheles funestus in Siaya County, western Kenya. Parasit Vectors 2024; 17:6. [PMID: 38178213 PMCID: PMC10768102 DOI: 10.1186/s13071-023-06096-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2023] [Accepted: 12/12/2023] [Indexed: 01/06/2024] Open
Abstract
BACKGROUND Spatial repellents (SR) may complement current vector control tools and provide additional coverage when people are not under their bednets or are outdoors. Here we assessed the efficacy of a metofluthrin-based SR in reducing exposure to pyrethroid-resistant Anopheles funestus in Siaya County, western Kenya. METHODS Metofluthrin was vaporized using an emanator configured to a liquid petroleum gas (LPG) canister, placed inside experimental huts (phase 1) or outdoors (phase 2), and evaluated for reductions in human landing rate, density, knockdown and mortality rates of An. funestus, which are present in high density in the area. To demonstrate the mosquito recruiting effect of LPG, a hut with only an LPG cooker but no metofluthrin was added as a comparator and compared with an LPG cooker burning alongside the emanator and a third hut with no LPG cooker as control. Phase 2 evaluated the protective range of the SR product while emanating from the centre of a team of mosquito collectors sitting outdoors in north, south, east and west directions at 5, 10 and 20 feet from the emanating device. RESULTS Combustion of LPG with a cook stove increased the density of An. funestus indoors by 51% over controls with no cook stove. In contrast, huts with metofluthrin vaporized with LPG combustion had lower indoor density of An. funestus (99.3% less than controls), with knockdown and mortality rates of 95.5 and 87.7%, respectively, in the mosquitoes collected in the treated huts. In the outdoor study (phase 2), the outdoor landing rate was significantly lower at 5 and 10 feet than at 20 feet from the emanator. CONCLUSIONS Vaporized metofluthrin almost completely prevented An. funestus landing indoors and led to 10 times lower landing rates within 10 feet of the emanator outdoors, the first product to demonstrate such potential. Cooking with LPG inside the house could increase exposure to Anopheles mosquito bites, but the use of the metofluthrin canister eliminates this risk.
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Affiliation(s)
- Silas Agumba
- Centre for Global Health Research, Kenya Medical Research Institute, P.O. Box 1578-40100, Kisumu, Kenya.
| | - Vincent Moshi
- Centre for Global Health Research, Kenya Medical Research Institute, P.O. Box 1578-40100, Kisumu, Kenya
| | - Margaret Muchoki
- Centre for Global Health Research, Kenya Medical Research Institute, P.O. Box 1578-40100, Kisumu, Kenya
| | - Seline Omondi
- Centre for Global Health Research, Kenya Medical Research Institute, P.O. Box 1578-40100, Kisumu, Kenya
| | - Jackline Kosgei
- Centre for Global Health Research, Kenya Medical Research Institute, P.O. Box 1578-40100, Kisumu, Kenya
| | - Edward D Walker
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, 48824, USA
| | - Bernard Abong'o
- Centre for Global Health Research, Kenya Medical Research Institute, P.O. Box 1578-40100, Kisumu, Kenya
| | - Nicole Achee
- Department of Biological Sciences, Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN, USA
| | - John Grieco
- Department of Biological Sciences, Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN, USA
| | - Eric Ochomo
- Centre for Global Health Research, Kenya Medical Research Institute, P.O. Box 1578-40100, Kisumu, Kenya.
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Benjamin-Chung J, Li H, Nguyen A, Heitmann GB, Bennett A, Ntuku H, Prach LM, Tambo M, Wu L, Drakeley C, Gosling R, Mumbengegwi D, Kleinschmidt I, Smith JL, Hubbard A, van der Laan M, Hsiang MS. Targeted malaria elimination interventions reduce Plasmodium falciparum infections up to 3 kilometers away. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2023:2023.09.19.23295806. [PMID: 37790419 PMCID: PMC10543053 DOI: 10.1101/2023.09.19.23295806] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 10/05/2023]
Abstract
Malaria elimination interventions in low-transmission settings aim to extinguish hot spots and prevent transmission to nearby areas. In malaria elimination settings, the World Health Organization recommends reactive, focal interventions targeted to the area near malaria cases shortly after they are detected. A key question is whether these interventions reduce transmission to nearby uninfected or asymptomatic individuals who did not receive interventions. Here, we measured direct effects (among intervention recipients) and spillover effects (among non-recipients) of reactive, focal interventions delivered within 500m of confirmed malaria index cases in a cluster-randomized trial in Namibia. The trial delivered malaria chemoprevention (artemether lumefantrine) and vector control (indoor residual spraying with Actellic) separately and in combination using a factorial design. We compared incidence, infection prevalence, and seroprevalence between study arms among intervention recipients (direct effects) and non-recipients (spillover effects) up to 3 km away from index cases. We calculated incremental cost-effectiveness ratios accounting for spillover effects. The combined chemoprevention and vector control intervention produced direct effects and spillover effects. In the primary analysis among non-recipients within 1 km from index cases, the combined intervention reduced malaria incidence by 43% (95% CI 20%, 59%). In secondary analyses among non-recipients 500m-3 km from interventions, the combined intervention reduced infection by 79% (6%, 95%) and seroprevalence 34% (20%, 45%). Accounting for spillover effects increased the cost-effectiveness of the combined intervention by 37%. Our findings provide the first evidence that targeting hot spots with combined chemoprevention and vector control interventions can indirectly benefit non-recipients up to 3 km away.
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Affiliation(s)
- Jade Benjamin-Chung
- Department of Epidemiology and Population Health, Stanford University, Stanford, United States
- Chan Zuckerberg Biohub, San Francisco, United States
| | - Haodong Li
- Division of Biostatistics, University of California, Berkeley
| | - Anna Nguyen
- Department of Epidemiology and Population Health, Stanford University, Stanford, United States
| | | | - Adam Bennett
- Malaria Elimination Initiative, Global Health Group, University of California, San Francisco (UCSF) , San Francisco, United States
- PATH, Seattle, United States
| | - Henry Ntuku
- Malaria Elimination Initiative, Global Health Group, University of California, San Francisco (UCSF) , San Francisco, United States
| | - Lisa M. Prach
- Malaria Elimination Initiative, Global Health Group, University of California, San Francisco (UCSF) , San Francisco, United States
| | - Munyaradzi Tambo
- Multidisciplinary Research Centre, University of Namibia, Windhoek, Namibia
| | - Lindsey Wu
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, UK
| | - Chris Drakeley
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, UK
| | - Roly Gosling
- Malaria Elimination Initiative, Global Health Group, University of California, San Francisco (UCSF) , San Francisco, United States
- Department of Disease Control, London School of Hygiene and Tropical Medicine, London, UK
| | | | - Immo Kleinschmidt
- MRC International Statistics and Epidemiology Group, Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, UK
- Wits Research Institute for Malaria, Wits/SAMRC Collaborating Centre for Multi-Disciplinary Research on Malaria, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
- Southern African Development Community Malaria Elimination Eight Secretariat, Windhoek, Namibia
| | - Jennifer L. Smith
- Malaria Elimination Initiative, Global Health Group, University of California, San Francisco (UCSF) , San Francisco, United States
| | - Alan Hubbard
- Division of Biostatistics, University of California, Berkeley
| | | | - Michelle S. Hsiang
- Chan Zuckerberg Biohub, San Francisco, United States
- Malaria Elimination Initiative, Global Health Group, University of California, San Francisco (UCSF) , San Francisco, United States
- Department of Epidemiology and Biostatistics, UCSF, San Francisco, United States
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18
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Skinner EB, Childs ML, Thomas MB, Cook J, Sternberg ED, Koffi AA, N'Guessan R, Wolie RZ, Oumbouke WA, Ahoua Alou LP, Brice S, Mordecai EA. Global malaria predictors at a localized scale. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2023:2023.11.20.23298800. [PMID: 38045403 PMCID: PMC10690354 DOI: 10.1101/2023.11.20.23298800] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/05/2023]
Abstract
Malaria is a life-threatening disease caused by Plasmodium parasites transmitted by Anopheles mosquitoes. In 2021, more than 247 million cases of malaria were reported worldwide, with an estimated 619,000 deaths. While malaria incidence has decreased globally in recent decades, some public health gains have plateaued, and many endemic hotspots still face high transmission rates. Understanding local drivers of malaria transmission is crucial but challenging due to the complex interactions between climate, entomological and human variables, and land use. This study focuses on highly climatically suitable and endemic areas in Côte d'Ivoire to assess the explanatory power of coarse climatic predictors of malaria transmission at a fine scale. Using data from 40 villages participating in a randomized controlled trial of a household malaria intervention, the study examines the effects of climate variation over time on malaria transmission. Through panel regressions and statistical modeling, the study investigates which variable (temperature, precipitation, or entomological inoculation rate) and its form (linear or unimodal) best explains seasonal malaria transmission and the factors predicting spatial variation in transmission. The results highlight the importance of temperature and rainfall, with quadratic temperature and all precipitation models performing well, but the causal influence of each driver remains unclear due to their strong correlation. Further, an independent, mechanistic temperature-dependent R 0 model based on laboratory data aligns well with observed malaria incidence rates, emphasizing the significance and predictability of temperature suitability across scales. By contrast, entomological variables, such as entomological inoculation rate, were not strong predictors of human incidence in this context. Finally, the study explores the predictors of spatial variation in malaria, considering land use, intervention, and entomological variables. The findings contribute to a better understanding of malaria transmission dynamics at local scales, aiding in the development of effective control strategies in endemic regions.
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Duguay C, Mosha JF, Lukole E, Mangalu D, Thickstun C, Mallya E, Aziz T, Feng C, Protopopoff N, Mosha F, Manjurano A, Krentel A, Kulkarni MA. Assessing risk factors for malaria and schistosomiasis among children in Misungwi, Tanzania, an area of co-endemicity: A mixed methods study. PLOS GLOBAL PUBLIC HEALTH 2023; 3:e0002468. [PMID: 37992045 PMCID: PMC10664891 DOI: 10.1371/journal.pgph.0002468] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Accepted: 10/16/2023] [Indexed: 11/24/2023]
Abstract
Malaria and schistosomiasis are two major parasitic vector-borne diseases that are a particular threat to young children in Sub-Saharan Africa. In the present study, we investigated factors that are associated with malaria, schistosomiasis, and co-infection among school-aged children, using an explanatory sequential mixed-methods approach. A cross-sectional study was conducted in January 2022 in Misungwi, Tanzania, that sampled 1,122 children aged 5 to 14 years old for malaria and schistosomiasis infection. Mixed-effect logistic regression models were used to assess the association between infection prevalence or seroprevalence, and environmental determinants that create favorable conditions for vectors and parasites and social determinants that relate to disease exposure. Community mapping combined with direct field observations were conducted in August 2022 in three selected villages from the cross-sectional study to understand specific water use behaviors and to identify potential malaria mosquito larval breeding sites and freshwater snail habitat. The prevalence of malaria, seroprevalence of schistosomiasis, and co-infection in this study were 40.4%, 94.3%, and 38.1%, respectively. Individual-level factors emerged as the primary determinants driving the association with infection, with age (every one-year increase in age) and sex (boys vs girls) being statistically and positively associated with malaria, schistosomiasis, and co-infection (P<0.05 for all). Community maps identified many unimproved water sources in all three villages that were used by humans, cattle, or both. We found that children primarily fetched water, and that unprotected wells were dedicated for drinking water whereas ponds were dedicated for other domestic uses and cattle. Although not identified in the community maps, we found hand pumps in all three villages were not in use because of unpleasant taste and high cost. This study improves our understanding of individual, social and environmental factors that are associated with malaria, schistosomiasis, and co-infection, which can inform potential entry points for integrated disease prevention and control.
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Affiliation(s)
- Claudia Duguay
- School of Epidemiology and Public Health, University of Ottawa, Ottawa, Canada
| | - Jacklin F. Mosha
- National Institute of Medical Research Tanzania, Mwanza Research Centre, Mwanza, Tanzania
| | - Eliud Lukole
- National Institute of Medical Research Tanzania, Mwanza Research Centre, Mwanza, Tanzania
| | - Doris Mangalu
- National Institute of Medical Research Tanzania, Mwanza Research Centre, Mwanza, Tanzania
| | - Charles Thickstun
- School of Epidemiology and Public Health, University of Ottawa, Ottawa, Canada
| | - Elizabeth Mallya
- Kilimanjaro Christian Medical University College, Moshi, Tanzania
| | - Tatu Aziz
- National Institute of Medical Research Tanzania, Mwanza Research Centre, Mwanza, Tanzania
| | - Cindy Feng
- Department of Community Health & Epidemiology, Dalhousie University, Halifax, Canada
| | - Natacha Protopopoff
- Faculty of Infectious and Tropical Diseases, Disease Control Department, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Franklin Mosha
- Kilimanjaro Christian Medical University College, Moshi, Tanzania
| | - Alphaxard Manjurano
- National Institute of Medical Research Tanzania, Mwanza Research Centre, Mwanza, Tanzania
| | - Alison Krentel
- School of Epidemiology and Public Health, University of Ottawa, Ottawa, Canada
- Bruyère Research Institute, Ottawa, Ontario, Canada
| | - Manisha A. Kulkarni
- School of Epidemiology and Public Health, University of Ottawa, Ottawa, Canada
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Mao W, Cooke R, Silimperi D, Urli Hodges E, Ortiz E, Udayakumar K. Scaling malaria interventions: bottlenecks to malaria elimination. BMJ Glob Health 2023; 8:e013378. [PMID: 37949501 PMCID: PMC10649629 DOI: 10.1136/bmjgh-2023-013378] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2023] [Accepted: 10/08/2023] [Indexed: 11/12/2023] Open
Abstract
The slow progress in malaria control efforts and increasing challenges have prompted a need to accelerate the research and development (R&D), launch and scaling of effective interventions for malaria elimination. This research, including desk research and key informant interviews, identified the following challenges along the end-to-end scale-up pathway of malaria interventions. Underinvestment in malaria R&D persists, and developers from low-resource settings are not commonly included in the R&D process. Unpredictable or unclear regulatory and policy pathways have been a hurdle. The private sector has not been fully engaged, which results in a less competitive market with few manufacturers, and consequently, a low supply of products. Persistent challenges also exist in the scaling of malaria interventions, such as the fragmentation of malaria programmes. Further efforts are needed to: (1) Strengthen coordination among stakeholders and especially the private sector to inform decisions and mobilise resources. (2) Increase engagement of national stakeholders, particularly those in low-income and middle-income countries, in planning for and implementing R&D, launching and scaling proven malaria interventions. (3) Use financial incentives and other market-shaping strategies to encourage R&D for innovative malaria products and improve existing interventions. (4) Streamline and improve transparency of WHO's prequalification and guidelines processes to provide timely technical advice and strategies for different settings. (5) Increase effort to integrate malaria services into the broader primary healthcare system. (6) Generate evidence to inform policies on improving access to malaria interventions.
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Affiliation(s)
- Wenhui Mao
- Duke Global Health Innovation Center, Duke University, Durham, North Carolina, USA
- Innovations in Healthcare, Durham, North Carolina, USA
| | - Rianna Cooke
- Duke Global Health Innovation Center, Duke University, Durham, North Carolina, USA
- Innovations in Healthcare, Durham, North Carolina, USA
| | - Diana Silimperi
- Duke Global Health Innovation Center, Duke University, Durham, North Carolina, USA
- Innovations in Healthcare, Durham, North Carolina, USA
| | - Elina Urli Hodges
- Duke Global Health Innovation Center, Duke University, Durham, North Carolina, USA
- Innovations in Healthcare, Durham, North Carolina, USA
| | - Ernesto Ortiz
- Duke Global Health Innovation Center, Duke University, Durham, North Carolina, USA
- Innovations in Healthcare, Durham, North Carolina, USA
| | - Krishna Udayakumar
- Duke Global Health Innovation Center, Duke University, Durham, North Carolina, USA
- Innovations in Healthcare, Durham, North Carolina, USA
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21
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Patouillard E, Han S, Lauer J, Barschkett M, Arcand JL. The Macroeconomic Impact of Increasing Investments in Malaria Control in 26 High Malaria Burden Countries: An Application of the Updated EPIC Model. Int J Health Policy Manag 2023; 12:7132. [PMID: 38618809 PMCID: PMC10590221 DOI: 10.34172/ijhpm.2023.7132] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Accepted: 09/04/2023] [Indexed: 04/16/2024] Open
Abstract
BACKGROUND Malaria remains a major public health problem. While globally malaria mortality affects predominantly young children, clinical malaria affects all age groups throughout life. Malaria not only threatens health but also child education and adult productivity while burdening government budgets and economic development. Increased investments in malaria control can contribute to reduce this burden but have an opportunity cost for the economy. Quantifying the net economic value of investing in malaria can encourage political and financial commitment. METHODS We adapted an existing macroeconomic model to simulate the effects of reducing malaria on the gross domestic product (GDP) of 26 high burden countries while accounting for the opportunity costs of increased investments in malaria. We compared two scenarios differing in their level of malaria investment and associated burden reduction: sustaining malaria control at 2015 intervention coverage levels, time at which coverage levels reached their historic peak and scaling-up coverage to reach the 2030 global burden reduction targets. We incorporated the effects that reduced malaria in children and young adolescents may have on the productivity of working adults and on the future size of the labour force augmented by educational returns, skills, and experience. We calibrated the model using estimates from linked epidemiologic and costing models on these same scenarios and from published country-specific macroeconomic data. RESULTS Scaling-up malaria control could produce a dividend of US$ 152 billion in the modelled countries, equivalent to 0.17% of total GDP projected over the study period across the 26 countries. Assuming a larger share of malaria investments is paid out from domestic savings, the dividend would be smaller but still significant, ranging between 0.10% and 0.14% of total projected GDP. Annual GDP gains were estimated to increase over time. Lower income and higher burden countries would experience higher gains. CONCLUSION Intensified malaria control can produce a multiplied return despite the opportunity cost of greater investments.
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Affiliation(s)
- Edith Patouillard
- Department of Health Financing and Economics, World Health Organization, Geneva, Switzerland
| | - Seoni Han
- Korea Institute for International Economic Policy, Sejong, Korea
| | - Jeremy Lauer
- Strathclyde Business School, University of Strathclyde, Glasgow, UK
| | - Mara Barschkett
- Federal Institute for Population Research and Department of Public Economics, German Institute of Economic Research (DIW Berlin), Berlin, Germany
| | - Jean-Louis Arcand
- Global Development Network, New Delhi, India
- Mohammed VI Polytechnic University, Rabat, Morocco
- Foundation for Studies and Research on International Development (FERDI), Clermont Ferrand, France
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22
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Liu R, Liu T, Dan T, Yang S, Li Y, Luo B, Zhuang Y, Fan X, Zhang X, Cai H, Teng Y. AIDMAN: An AI-based object detection system for malaria diagnosis from smartphone thin-blood-smear images. PATTERNS (NEW YORK, N.Y.) 2023; 4:100806. [PMID: 37720337 PMCID: PMC10499858 DOI: 10.1016/j.patter.2023.100806] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 03/02/2023] [Accepted: 07/07/2023] [Indexed: 09/19/2023]
Abstract
Malaria is a significant public health concern, with ∼95% of cases occurring in Africa, but accurate and timely diagnosis is problematic in remote and low-income areas. Here, we developed an artificial intelligence-based object detection system for malaria diagnosis (AIDMAN). In this system, the YOLOv5 model is used to detect cells in a thin blood smear. An attentional aligner model (AAM) is then applied for cellular classification that consists of multi-scale features, a local context aligner, and multi-scale attention. Finally, a convolutional neural network classifier is applied for diagnosis using blood-smear images, reducing interference caused by false positive cells. The results demonstrate that AIDMAN handles interference well, with a diagnostic accuracy of 98.62% for cells and 97% for blood-smear images. The prospective clinical validation accuracy of 98.44% is comparable to that of microscopists. AIDMAN shows clinically acceptable detection of malaria parasites and could aid malaria diagnosis, especially in areas lacking experienced parasitologists and equipment.
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Affiliation(s)
- Ruicun Liu
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China
| | - Tuoyu Liu
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China
| | - Tingting Dan
- School of Computer Science and Engineering, South China University of Technology, Guangzhou 510600, China
| | - Shan Yang
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China
| | - Yanbing Li
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China
| | - Boyu Luo
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China
| | - Yingtan Zhuang
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China
| | - Xinyue Fan
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China
| | - Xianchao Zhang
- Key Laboratory of Medical Electronics and Digital Health of Zhejiang Province, Jiaxing University, Jiaxing 314001, China
- Engineering Research Center of Intelligent Human Health Situation Awareness of Zhejiang Province, Jiaxing University, Jiaxing 314001, China
| | - Hongmin Cai
- School of Computer Science and Engineering, South China University of Technology, Guangzhou 510600, China
| | - Yue Teng
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China
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23
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Chen I, Ishengoma DS. Ganaplacide plus lumefantrine solid dispersion formulation: considerations for development and rollout. THE LANCET. INFECTIOUS DISEASES 2023; 23:990-992. [PMID: 37327810 DOI: 10.1016/s1473-3099(23)00231-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Accepted: 03/30/2023] [Indexed: 06/18/2023]
Affiliation(s)
- Ingrid Chen
- University of California, San Francisco, CA 94158, USA.
| | - Deus S Ishengoma
- National Institute for Medical Research, Dar Es Salaam, Tanzania; Harvard TH Chan School of Public Health, Boston, MA, USA; Faculty of Pharmaceutical Sciences, Monash University, Melbourne, VIC, Australia
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24
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Chen I, Doum D, Mannion K, Hustedt J, Sovannaroth S, McIver D, Macdonald M, Lobo N, Tatarsky A, Handley MA, Neukom J. Applying the COM-B behaviour change model to a pilot study delivering volatile pyrethroid spatial repellents and insecticide-treated clothing to forest-exposed populations in Mondulkiri Province, Cambodia. Malar J 2023; 22:251. [PMID: 37658337 PMCID: PMC10472618 DOI: 10.1186/s12936-023-04685-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Accepted: 08/22/2023] [Indexed: 09/03/2023] Open
Abstract
BACKGROUND Southeast Asia is making tremendous progress towards their 2030 malaria elimination goal but needs new interventions to stop forest malaria. This study trials two new vector control tools, a volatile pyrethroid spatial repellent (VPSR) and insecticide-treated clothing (ITC), amongst forest-exposed populations in Mondulkiri Province Cambodia to inform their potential use for eliminating forest malaria. METHODS 21 forest-exposed individuals were given a questionnaire on their perceptions of malaria and preventive practices used, after which they trialed two products sequentially. Clothes was treated with ITC by the study team. Mixed methods were used to understand their experience, attitudes, and preferences regarding the products trialed. Quantitative data was summarized and qualitative insights were analysed using thematic analysis, applying the Capability, Opportunity, and Motivation Behaviour Change (COM-B) model and Behaviour Change Wheel Framework to identify intervention functions to support tailored product rollout amongst these populations. RESULTS Study participants reported a need for protection from mosquito bites in outdoor and forest-exposed settings and perceived both products trialed to be effective for this purpose. The VPSR product was preferred when travel was not required, whereas ITC was preferred for ease of use when going to the forest, especially in rainy conditions. COM-B analysis identified that key enablers for use of both products included their perceived efficacy and ease of use, which required no skill or preparation. For barriers to use, the odour of ITC was sometimes perceived as being toxic, as well as its inability to protect uncovered skin from mosquito bites, while the perceived usefulness of the VPSR product trialed was limited by its water sensitivity in rainy forest settings. Intervention components to encourage appropriate and sustained use of these products include education about how to use these products and what to expect, persuasion to use them from community leaders and targeted channels, and enablement to facilitate convenient and affordable access. CONCLUSION The rollout of VPSRs and ITC amongst forest-exposed populations can be useful for eliminating malaria in Southeast Asia. Study findings can be applied to increase product uptake among forest exposed populations in Cambodia, while manufacturers can aim to develop products that are rainproof, easy to use in forest settings, and have favourable odour profiles to target users.
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Affiliation(s)
- Ingrid Chen
- Malaria Elimination Initiative, Institute for Global Health Sciences, University of California, San Francisco, USA.
| | - Dyna Doum
- Health Forefront Organization, Phnom Penh, Cambodia
| | - Kylie Mannion
- Menzies School of Health Research, Charles Darwin University, Casuarina, Australia
| | - John Hustedt
- Malaria Elimination Initiative, Institute for Global Health Sciences, University of California, San Francisco, USA
| | - Siv Sovannaroth
- National Center for Parasitology, Entomology and Malaria Control, Phnom Penh, Cambodia
| | - David McIver
- Malaria Elimination Initiative, Institute for Global Health Sciences, University of California, San Francisco, USA
| | | | - Neil Lobo
- University of Notre Dame, Notre Dame, IN, USA
| | - Allison Tatarsky
- Malaria Elimination Initiative, Institute for Global Health Sciences, University of California, San Francisco, USA
| | - Margaret A Handley
- Malaria Elimination Initiative, Institute for Global Health Sciences, University of California, San Francisco, USA
| | - Josselyn Neukom
- Malaria Elimination Initiative, Institute for Global Health Sciences, University of California, San Francisco, USA
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Sagna AB, Zéla L, Ouedraogo COW, Pooda SH, Porciani A, Furnival-Adams J, Lado P, Somé AF, Pennetier C, Chaccour CJ, Dabiré RK, Mouline K. Ivermectin as a novel malaria control tool: Getting ahead of the resistance curse. Acta Trop 2023; 245:106973. [PMID: 37352998 DOI: 10.1016/j.actatropica.2023.106973] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Revised: 06/14/2023] [Accepted: 06/16/2023] [Indexed: 06/25/2023]
Abstract
Reduction in malaria clinical cases is strongly dependent on the ability to prevent Anopheles infectious bites. Vector control strategies using long-lasting insecticidal nets and indoor residual spraying with insecticides have contributed to significantly reduce the incidence of malaria in many endemic countries, especially in the Sub-Saharan region. However, global progress in reducing malaria cases has plateaued since 2015 mostly due to the increased insecticide resistance and behavioral changes in Anopheles vectors. Additional control strategies are thus required to further reduce the burden of malaria and contain the spread of resistant and invasive Anopheles vectors. The use of endectocides such as ivermectin as an additional malaria control tool is now receiving increased attention, driven by its different mode of action compared to insecticides used so far and its excellent safety record for humans. In this opinion article, we discuss the advantages and disadvantages of using ivermectin for malaria control with a focus on the risk of selecting ivermectin resistance in malaria vectors. We also highlight the importance of understanding how ivermectin resistance could develop in mosquitoes and what its underlying mechanisms and associated molecular markers are, and propose a research agenda to manage this phenomenon.
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Affiliation(s)
- André B Sagna
- MIVEGEC, University of Montpellier, IRD, CNRS, Montpellier, France.
| | - Lamidi Zéla
- Centre International de Recherche-Développement sur l'Elevage en zone Subhumide, Bobo-Dioulasso, Burkina Faso
| | - Cheick Oumar W Ouedraogo
- Institut de Recherche en Sciences de la Santé, Direction Régionale de l'Ouest, Centre National de Recherche Scientifique et Technologique, Bobo-Dioulasso, Burkina Faso
| | - Sié H Pooda
- Centre International de Recherche-Développement sur l'Elevage en zone Subhumide, Bobo-Dioulasso, Burkina Faso; Université de Dédougou, Dédougou, Burkina Faso
| | | | | | - Paula Lado
- Center for Vector-borne Infectious Diseases, Colorado State University, Fort Collins, CO, USA
| | - Anyirékun F Somé
- Institut de Recherche en Sciences de la Santé, Direction Régionale de l'Ouest, Centre National de Recherche Scientifique et Technologique, Bobo-Dioulasso, Burkina Faso
| | - Cédric Pennetier
- MIVEGEC, University of Montpellier, IRD, CNRS, Montpellier, France
| | - Carlos J Chaccour
- ISGlobal, Barcelona Institute for Global Health, Barcelona, Spain; Centro de Investigación Biomédica en Red de Enfermedades Infecciosas, Madrid, Spain; Universidad de Navarra, Pamplona, Spain
| | - Roch K Dabiré
- Institut de Recherche en Sciences de la Santé, Direction Régionale de l'Ouest, Centre National de Recherche Scientifique et Technologique, Bobo-Dioulasso, Burkina Faso
| | - Karine Mouline
- MIVEGEC, University of Montpellier, IRD, CNRS, Montpellier, France
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Searle KM, Earland D, Francisco A, Muhiro V, Novela A, Ferrão J. Household structure is independently associated with malaria risk in rural Sussundenga, Mozambique. FRONTIERS IN EPIDEMIOLOGY 2023; 3:1137040. [PMID: 38455901 PMCID: PMC10911029 DOI: 10.3389/fepid.2023.1137040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/03/2023] [Accepted: 07/26/2023] [Indexed: 03/09/2024]
Abstract
Introduction Mozambique has the fourth highest malaria cases and malaria mortality globally. Locally, malaria incidence increases from low in the southern region to high in the central and northern regions. Manica Province in central Mozambique has the fourth highest prevalence of malaria out of the 11 provinces, and the highest in the central region of the country. In this area where coverage of interventions has been limited, household level risk factors can be important for understanding the natural history of infection, as well as the implementation of current and future interventions. There has been indication that the relationship between household structure and malaria risk is actually a mediating one between the true relationship between household income and education and Plasmodium falciparum infection. The objective of this study was to determine and quantify these complex relationships. Methods We conducted a community-based cross-sectional study in Sussundenga village. Sussundenga is a rural village, located in Sussundenga District, Manica Province, Mozambique. We enrolled 303 participants from 83 randomly selected households. We collected information on demographics, household construction, and administered a P. falciparum rapid diagnostic test (RDT). We constructed several generalized estimating equations logistic regression models to determine the independent effects of housing construction on malaria risk. We also constructed models separate from generalized estimating equations logistic mediation models to determine the proportion of effects mediated by household construction material in the relationship between head of household occupation and education and malaria risk. Results The overall malaria prevalence among the study population by RDT was 30.8%. In the multivariable model adjusting for all individual and household factors as potential confounders, rudimentary roof structure was the only household structural variable that was statistically significantly associated with increased malaria risk [OR 2.41 (1.03-5.63)]. We found no evidence that household structure mediated the relationship between head of household education or employment and malaria risk in our study population. Discussion Household structure was a significant risk factor for malaria infection in our study population. These findings are consistent with malaria being a disease of poverty and an area that could be targeted for future interventions that could have long-term impacts.
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Affiliation(s)
- Kelly M. Searle
- Division of Epidemiology and Community Health, University of Minnesota School of Public Health, Minneapolis, MN, United States
| | - Dominique Earland
- Division of Epidemiology and Community Health, University of Minnesota School of Public Health, Minneapolis, MN, United States
| | | | - Valy Muhiro
- Sussundenge-Sede Centro de Saude Rural, Sussundenga, Mozambique
| | - Anisío Novela
- Sussundenge-Sede Centro de Saude Rural, Sussundenga, Mozambique
| | - João Ferrão
- UniSCED Aberta de Mozambique, Chimoio, Mozambique
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Ciubotariu II, Monroe A, Williams NA, Ogoma SB, Okumu F. Ifakara MasterClasses: lessons from leading experts on the battle against malaria. Trends Parasitol 2023; 39:607-614. [PMID: 37331883 DOI: 10.1016/j.pt.2023.05.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Accepted: 05/24/2023] [Indexed: 06/20/2023]
Affiliation(s)
- Ilinca I Ciubotariu
- Department of Biological Sciences, Purdue University, West Lafayette, IN, USA.
| | - April Monroe
- Johns Hopkins Center for Communication Programs, Baltimore, MD, USA; Ifakara Health Institute, Ifakara, Tanzania.
| | - Nana Aba Williams
- MESA Alliance, Barcelona Institute for Global Health (ISGlobal), Barcelona, Spain; Barcelona Institute for Global Health (ISGlobal), Hospital Clínic-Universitat de Barcelona, Barcelona, Spain.
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Jobe NB, Huijben S, Paaijmans KP. Non-target effects of chemical malaria vector control on other biological and mechanical infectious disease vectors. Lancet Planet Health 2023; 7:e706-e717. [PMID: 37558351 DOI: 10.1016/s2542-5196(23)00136-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Revised: 06/09/2023] [Accepted: 06/17/2023] [Indexed: 08/11/2023]
Abstract
Public health insecticides play a crucial role in malaria control and elimination programmes. Many other arthropods, including mechanical and biological vectors of infectious diseases, have similar indoor feeding or resting behaviours, or both, as malaria mosquitoes, and could be exposed to the same insecticides. In this Personal View, we show that little is known about the insecticide susceptibility status and the extent of exposure to malaria interventions of other arthropod species. We highlight that there is an urgent need to better understand the selection pressure for insecticide resistance in those vectors, to ensure current and future active ingredients remain effective in targeting a broad range of arthropod species, allowing us to prevent and control future outbreaks of infectious diseases other than malaria.
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Affiliation(s)
- Ndey Bassin Jobe
- The Center for Evolution & Medicine, School of Life Sciences, Arizona State University, Tempe, AZ, USA
| | - Silvie Huijben
- The Center for Evolution & Medicine, School of Life Sciences, Arizona State University, Tempe, AZ, USA; Simon A Levin Mathematical, Computational and Modeling Sciences Center, Arizona State University, Tempe, AZ, USA
| | - Krijn P Paaijmans
- The Center for Evolution & Medicine, School of Life Sciences, Arizona State University, Tempe, AZ, USA; Simon A Levin Mathematical, Computational and Modeling Sciences Center, Arizona State University, Tempe, AZ, USA; The Biodesign Center for Immunotherapy, Vaccines and Virotherapy, Arizona State University, Tempe, AZ, USA; ISGlobal, Barcelona, Spain; Centro de Investigação em Saúde de Manhiça, Maputo, Mozambique.
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Quaye IK, Aleksenko L, Paganotti GM, Peloewetse E, Haiyambo DH, Ntebela D, Oeuvray C, Greco B. Malaria Elimination in Africa: Rethinking Strategies for Plasmodium vivax and Lessons from Botswana. Trop Med Infect Dis 2023; 8:392. [PMID: 37624330 PMCID: PMC10458071 DOI: 10.3390/tropicalmed8080392] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2023] [Revised: 07/21/2023] [Accepted: 07/22/2023] [Indexed: 08/26/2023] Open
Abstract
The global malaria community has picked up the theme of malaria elimination in more than 90% of the world's population in the next decade. Recent reports of Plasmodium vivax (P. vivax) in sub-Saharan Africa, including in Duffy-negative individuals, threaten the efforts aimed at achieving elimination. This is not only in view of strategies that are tailored only to P. falciparum elimination but also due to currently revealed biological characteristics of P. vivax concerning the relapse patterns of hypnozoites and conservation of large biomasses in cryptic sites in the bone marrow and spleen. A typical scenario was observed in Botswana between 2008 and 2018, which palpably projects how P. vivax could endanger malaria elimination efforts where the two parasites co-exist. The need for the global malaria community, national malaria programs (NMPs), funding agencies and relevant stakeholders to engage in a forum to discuss and recommend clear pathways for elimination of malaria, including P. vivax, in sub-Saharan Africa is warranted.
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Affiliation(s)
- Isaac K. Quaye
- Pan African Vivax and Ovale Network, Faculty of Engineering Computer and Allied Sciences, Regent University College of Science and Technology, #1 Regent Ave, McCarthy Hill, Mendskrom, Dansoman, Accra P.O. Box DS1636, Ghana
| | - Larysa Aleksenko
- Department of Health Sciences, School of Public Health, College of Health, Medicine and Life Sciences, Brunel University, Kingston Lane, Uxbridge, Middlesex, London UB8 3PH, UK;
| | - Giacomo M. Paganotti
- Botswana-University of Pennsylvania Partnership, Riverwalk, Gaborone P.O. Box 45498, Botswana;
- Division of Infectious Diseases, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Elias Peloewetse
- Department of Biological Sciences, Faculty of Sciences, University of Botswana, Gaborone Private Bag 00704, Botswana;
| | - Daniel H. Haiyambo
- Department of Human, Biological and Translational Medical Sciences, Faculty of Health Sciences and Veterinary Medicine, University of Namibia School of Medicine, Hage Geingob Campus, Windhoek Private Bag 13301, Namibia;
| | - Davies Ntebela
- National Malaria Program, Ministry of Health, Gaborone Private Bag 0038, Botswana;
| | - Claude Oeuvray
- Global Health Institute of Merck, Terre Bonne Building Z0, Route de Crassier 1, Eysin, 1266 Geneva, Switzerland; (C.O.); (B.G.)
| | - Beatrice Greco
- Global Health Institute of Merck, Terre Bonne Building Z0, Route de Crassier 1, Eysin, 1266 Geneva, Switzerland; (C.O.); (B.G.)
| | - the PAVON Consortium
- PAVON, Regent University College of Science and Technology, #1 Regent Avenue, McCarthy Hiil, Mendskrom, Dansoman, Accra P.O. Box DS1636, Ghana
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Nguyen TD, Tran TNA, Parker DM, White NJ, Boni MF. Antimalarial mass drug administration in large populations and the evolution of drug resistance. PLOS GLOBAL PUBLIC HEALTH 2023; 3:e0002200. [PMID: 37494337 PMCID: PMC10370688 DOI: 10.1371/journal.pgph.0002200] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2023] [Accepted: 06/30/2023] [Indexed: 07/28/2023]
Abstract
Mass drug administration (MDA) with antimalarials has been shown to reduce prevalence and interrupt transmission in small populations, in populations with reliable access to antimalarial drugs, and in populations where sustained improvements in diagnosis and treatment are possible. In addition, when MDA is effective it eliminates both drug-resistant parasites and drug-sensitive parasites, which has the long-term benefit of extending the useful therapeutic life of first-line therapies for all populations, not just the focal population where MDA was carried out. However, in order to plan elimination measures effectively, it is necessary to characterize the conditions under which failed MDA could exacerbate resistance. We use an individual-based stochastic model of Plasmodium falciparum transmission to evaluate this risk for MDA using dihydroartemisinin-piperaquine (DHA-PPQ), in populations where access to antimalarial treatments may not be uniformly high and where re-importation of drug-resistant parasites may be common. We find that artemisinin-resistance evolution at the kelch13 locus can be accelerated by MDA when all three of the following conditions are met: (1) strong genetic bottlenecking that falls short of elimination, (2) re-importation of artemisinin-resistant genotypes, and (3) continued selection pressure during routine case management post-MDA. Accelerated resistance levels are not immediate but follow the rebound of malaria cases post-MDA, if this is allowed to occur. Crucially, resistance is driven by the selection pressure during routine case management post-MDA and not the selection pressure exerted during the MDA itself. Second, we find that increasing treatment coverage post-MDA increases the probability of local elimination in low-transmission regions (prevalence < 2%) in scenarios with both low and high levels of drug-resistance importation. This emphasizes the importance of planning for and supporting high coverage of diagnosis and treatment post-MDA.
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Affiliation(s)
- Tran Dang Nguyen
- Center for Infectious Disease Dynamics, Department of Biology, Pennsylvania State University, PA, United States of America
| | - Thu Nguyen-Anh Tran
- Center for Infectious Disease Dynamics, Department of Biology, Pennsylvania State University, PA, United States of America
| | - Daniel M Parker
- Department of Population Health and Disease Prevention, Department of Epidemiology and Biostatistics, University of California, Irvine, Irvine, CA, United States of America
| | - Nicholas J White
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
- Mahidol-Oxford Research Unit, Wellcome Trust Major Overseas Programme, Mahidol University, Bangkok, Thailand
| | - Maciej F Boni
- Center for Infectious Disease Dynamics, Department of Biology, Pennsylvania State University, PA, United States of America
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
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Perrotti E, L'Episcopia M, Menegon M, Soares IS, Rosas-Aguirre A, Speybroeck N, LLanos-Cuentas A, Menard D, Ferreira MU, Severini C. Reduced polymorphism of Plasmodium vivax early transcribed membrane protein (PvETRAMP) 11.2. Parasit Vectors 2023; 16:238. [PMID: 37461081 DOI: 10.1186/s13071-023-05851-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Accepted: 06/27/2023] [Indexed: 07/20/2023] Open
Abstract
BACKGROUND ETRAMP11.2 (PVX_003565) is a well-characterized protein with antigenic potential. It is considered to be a serological marker for diagnostic tools, and it has been suggested as a potential vaccine candidate. Despite its immunological relevance, the polymorphism of the P. vivax ETRAMP11.2 gene (pvetramp11.2) remains undefined. The genetic variability of an antigen may limit the effectiveness of its application as a serological surveillance tool and in vaccine development and, therefore, the aim of this study was to investigate the genetic diversity of pvetramp11.2 in parasite populations from Amazonian regions and worldwide. We also evaluated amino acid polymorphism on predicted B-cell epitopes. The low variability of the sequence encoding PvETRAMP11.2 protein suggests that it would be a suitable marker in prospective serodiagnostic assays for surveillance strategies or in vaccine design against P. vivax malaria. METHODS The pvetramp11.2 of P. vivax isolates collected from Brazil (n = 68) and Peru (n = 36) were sequenced and analyzed to assess nucleotide polymorphisms, allele distributions, population differentiation, genetic diversity and signature of selection. In addition, sequences (n = 104) of seven populations from different geographical regions were retrieved from the PlasmoDB database and included in the analysis to study the worldwide allele distribution. Potential linear B-cell epitopes and their polymorphisms were also explored. RESULTS The multiple alignments of 208 pvetramp11.2 sequences revealed a low polymorphism and a marked geographical variation in allele diversity. Seven polymorphic sites and 11 alleles were identified. All of the alleles were detected in isolates from the Latin American region and five alleles were detected in isolates from the Southeast Asia/Papua New Guinea (SEA/PNG) region. Three alleles were shared by all Latin American populations (H1, H6 and H7). The H1 allele (reference allele from Salvador-1 strain), which was absent in the SEA/PNG populations, was the most represented allele in populations from Brazil (54%) and was also detected at high frequencies in populations from all other Latin America countries (range: 13.0% to 33.3%). The H2 allele was the major allele in SEA/PNG populations, but was poorly represented in Latin America populations (only in Brazil: 7.3%). Plasmodium vivax populations from Latin America showed a marked inter-population genetic differentiation (fixation index [Fst]) in contrast to SEA/PNG populations. Codon bias measures (effective number of codons [ENC] and Codon bias index [CBI]) indicated preferential use of synonymous codons, suggesting selective pressure at the translation level. Only three amino acid substitutions, located in the C-terminus, were detected. Linear B-cell epitope mapping predicted two epitopes in the Sal-1 PvETRAMP11.2 protein, one of which was fully conserved in all of the parasite populations analyzed. CONCLUSIONS We provide an overview of the allele distribution and genetic differentiation of ETRAMP11.2 antigen in P. vivax populations from different endemic areas of the world. The reduced polymorphism and the high degree of protein conservation supports the application of PvETRAMP11.2 protein as a reliable antigen for application in serological assays or vaccine design. Our findings provide useful information that can be used to inform future study designs.
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Affiliation(s)
- Edvige Perrotti
- Department of Infectious Diseases, Istituto Superiore Di Sanità, Rome, Italy.
| | | | - Michela Menegon
- Department of Infectious Diseases, Istituto Superiore Di Sanità, Rome, Italy
| | - Irene S Soares
- Department of Clinical and Toxicological Analyses, School of Pharmaceutical Sciences, University of São Paulo, São Paulo, Brazil
| | - Angel Rosas-Aguirre
- Research Institute of Health and Society (IRSS), Université Catholique de Louvain, Brussels, Belgium
- Instituto de Medicina Tropical "Alexander Von Humboldt", Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Niko Speybroeck
- Research Institute of Health and Society (IRSS), Université Catholique de Louvain, Brussels, Belgium
| | - Alejandro LLanos-Cuentas
- Instituto de Medicina Tropical "Alexander Von Humboldt", Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Didier Menard
- Laboratoire de Parasitologie Et Mycologie Médicale, Les Hôpitaux Universitaires de Strasbourg, Strasbourg, France
- Institut de Parasitologie Et Pathologie Tropicale, Université de Strasbourg, Strasbourg, France
- Malaria Genetics and Resistance Unit-INSERM U1201, Institut Pasteur, Paris, France
| | - Marcelo Urbano Ferreira
- Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
- Global Health and Tropical Medicine, Instituto de Higiene e Medicina Tropical, Universidade NOVA de Lisboa, Lisbon, Portugal
| | - Carlo Severini
- Department of Infectious Diseases, Istituto Superiore Di Sanità, Rome, Italy.
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James SL, Quemada H, Benedict MQ, Dass B. Requirements for market entry of gene drive-modified mosquitoes for control of vector-borne diseases: analogies to other biologic and biotechnology products. Front Bioeng Biotechnol 2023; 11:1205865. [PMID: 37362219 PMCID: PMC10285705 DOI: 10.3389/fbioe.2023.1205865] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Accepted: 05/25/2023] [Indexed: 06/28/2023] Open
Abstract
Gene drive-modified mosquitoes (GDMMs) are proposed as new tools for control and elimination of malaria and other mosquito-borne diseases, and promising results have been observed from testing conducted in containment. Although still at an early stage of development, it is important to begin now to consider approval procedures and market entry strategies for the eventual implementation of GDMMs in the context of disease control programs, as these could impact future research plans. It is expected that, as for other types of new products, those seeking to bring GDMMs to market will be required to provide sufficient information to allow the regulator(s) to determine whether the product is safe and effective for its proposed use. There already has been much emphasis on developing requirements for the biosafety components of the "safe and effective" benchmark, largely concerned with their regulation as genetically modified organisms. Other potential approval requirements have received little attention, however. Although GDMMs are expected to be implemented primarily in the context of public health programs, any regulatory analogies to other public health products, such as pharmaceuticals, vaccines, or chemical pesticides, must take into account the characteristics of live mosquito products. Typical manufacturing standards related to product identity, potency or quality will need to be adapted to GDMMs. Valuable lessons can be drawn from the regulatory approval processes for other whole organism and genetically modified (GM) organism products. Supply chain requirements, such as scale of production, location and design of production facilities, and methods of distribution and delivery, will be dependent upon the characteristics of the particular GDMM product, the conditions of use, and the region to be served. Plans for fulfilling supply chain needs can build upon experience in the development of other live insect products for use in public health and agriculture. Implementation of GDMMs would benefit from additional research on enabling technologies for long-term storage of mosquito life stages, efficient mass production, and area-wide delivery of GDMMs. Early consideration of these practical requirements for market entry will help to mitigate downstream delays in the development of these promising new technologies.
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Affiliation(s)
- Stephanie L. James
- GeneConvene Global Collaborative, Foundation for the NIH, Bethesda, MD, United States
| | | | | | - Brinda Dass
- GeneConvene Global Collaborative, Foundation for the NIH, Bethesda, MD, United States
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Chen I, Doum D, Mannion K, Hustedt J, Sovannaroth S, McIver D, Macdonald M, Lobo NF, Tatarsky A, Handley M, Neukom J. Applying the COM-B behavior model to inform the delivery of spatial repellents and insecticide-treated clothing among forest exposed populations in Mondulkiri Province, Cambodia. RESEARCH SQUARE 2023:rs.3.rs-2874672. [PMID: 37205382 PMCID: PMC10187415 DOI: 10.21203/rs.3.rs-2874672/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
BACKGROUND Southeast Asia is making tremendous progress towards their 2030 malaria elimination goal but needs new interventions to stop forest malaria. This study trials two new vector control tools, a volatile pyrethroid spatial repellent (VSPR) and insecticide-treated clothing (ITC), amongst forest-exposed populations in Mondulkiri Province Cambodia to inform their potential use for eliminating forest malaria. METHODS 21 forest-exposed individuals were given a questionnaire on their perceptions of malaria and preventive practices used, after which they trialed two products sequentially. Mixed methods were used to understand their experience, attitudes, and preferences regarding the products trialed. Quantitative data was summarized and qualitative insights were analyzed using thematic analysis, applying the Capability, Opportunity, Motivation Behavior Change (COM-B) model and Behavior Change Wheel Framework to identify intervention functions to support tailored product rollout amongst these populations. RESULTS Study participants reported a need for protection from mosquito bites in outdoor and forest-exposed settings and perceived both products trialed to be effective for this purpose. The VPSR product was preferred when travel was not required, whereas ITC was preferred for ease of use when going to the forest, especially in rainy conditions. COM-B analysis identified that key enablers for use of both products included their perceived efficacy and ease of use, which required no skill or preparation. For barriers to use, the odor of ITC was sometimes perceived as being toxic, as well as its inability to protect uncovered skin from mosquito bites, while the perceived usefulness of the VPSR product trialed was limited by its water sensitivity in rainy forest settings. Intervention components to encourage appropriate and sustained use of these products include education about how to use these products and what to expect, persuasion to use them from community leaders and targeted ads, and enablement to guarantee access. CONCLUSION The rollout of VPSRs and ITC amongst forest-exposed populations can be useful for eliminating malaria in Southeast Asia. Study findings can be applied to increase product uptake in Cambodia, while research efforts can aim to develop products that are rainproof, easy to use in forest settings, and have favorable odor profiles to target users.
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Affiliation(s)
| | | | | | - John Hustedt
- United States Agency for International Development
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Bertozzi-Villa A, Bever CA, Gerardin J, Proctor JL, Wu M, Harding D, Hollingsworth TD, Bhatt S, Gething PW. An archetypes approach to malaria intervention impact mapping: a new framework and example application. Malar J 2023; 22:138. [PMID: 37101269 PMCID: PMC10131392 DOI: 10.1186/s12936-023-04535-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Accepted: 03/15/2023] [Indexed: 04/28/2023] Open
Abstract
BACKGROUND As both mechanistic and geospatial malaria modeling methods become more integrated into malaria policy decisions, there is increasing demand for strategies that combine these two methods. This paper introduces a novel archetypes-based methodology for generating high-resolution intervention impact maps based on mechanistic model simulations. An example configuration of the framework is described and explored. METHODS First, dimensionality reduction and clustering techniques were applied to rasterized geospatial environmental and mosquito covariates to find archetypal malaria transmission patterns. Next, mechanistic models were run on a representative site from each archetype to assess intervention impact. Finally, these mechanistic results were reprojected onto each pixel to generate full maps of intervention impact. The example configuration used ERA5 and Malaria Atlas Project covariates, singular value decomposition, k-means clustering, and the Institute for Disease Modeling's EMOD model to explore a range of three-year malaria interventions primarily focused on vector control and case management. RESULTS Rainfall, temperature, and mosquito abundance layers were clustered into ten transmission archetypes with distinct properties. Example intervention impact curves and maps highlighted archetype-specific variation in efficacy of vector control interventions. A sensitivity analysis showed that the procedure for selecting representative sites to simulate worked well in all but one archetype. CONCLUSION This paper introduces a novel methodology which combines the richness of spatiotemporal mapping with the rigor of mechanistic modeling to create a multi-purpose infrastructure for answering a broad range of important questions in the malaria policy space. It is flexible and adaptable to a range of input covariates, mechanistic models, and mapping strategies and can be adapted to the modelers' setting of choice.
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Affiliation(s)
- Amelia Bertozzi-Villa
- Institute for Disease Modeling, Bill & Melinda Gates Foundation, Seattle, USA.
- Malaria Atlas Project, Telethon Kids Institute, Perth, Australia.
- Big Data Institute, Nuffield Department of Medicine, Oxford University, Oxford, UK.
| | - Caitlin A Bever
- Institute for Disease Modeling, Bill & Melinda Gates Foundation, Seattle, USA
| | - Jaline Gerardin
- Institute for Disease Modeling, Bill & Melinda Gates Foundation, Seattle, USA
- Department of Preventive Medicine and Institute for Global Health, Northwestern University, Chicago, USA
| | - Joshua L Proctor
- Institute for Disease Modeling, Bill & Melinda Gates Foundation, Seattle, USA
| | - Meikang Wu
- Institute for Disease Modeling, Bill & Melinda Gates Foundation, Seattle, USA
| | - Dennis Harding
- Institute for Disease Modeling, Bill & Melinda Gates Foundation, Seattle, USA
| | | | - Samir Bhatt
- MRC Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, Imperial College, London, UK
- Section of Epidemiology, Department of Public Health, University of Copenhagen, Copenhagen, Denmark
| | - Peter W Gething
- Malaria Atlas Project, Telethon Kids Institute, Perth, Australia
- Curtin University, Perth, Australia
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Porta EOJ, Ballari MS, Carlucci R, Wilkinson S, Ma G, Tekwani BL, Labadie GR. Systematic study of 1,2,3-triazolyl sterols for the development of new drugs against parasitic Neglected Tropical Diseases. Eur J Med Chem 2023; 254:115378. [PMID: 37084599 DOI: 10.1016/j.ejmech.2023.115378] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2022] [Revised: 04/11/2023] [Accepted: 04/12/2023] [Indexed: 04/23/2023]
Abstract
A series of thirty 1,2,3-triazolylsterols, inspired by azasterols with proven antiparasitic activity, were prepared by a stereocontrolled synthesis. Ten of these compounds constitute chimeras/hybrids of 22,26-azasterol (AZA) and 1,2,3-triazolyl azasterols. The entire library was assayed against the kinetoplastid parasites Leishmania donovani, Trypanosoma cruzi, and Trypanosoma brucei, the causatives agents for visceral leishmaniasis, Chagas disease, and sleeping sickness, respectively. Most of the compounds were active at submicromolar/nanomolar concentrations with high selectivity index, when compared to their cytotoxicity against mammalian cells. Analysis of in silico physicochemical properties were conducted to rationalize the activities against the neglected tropical disease pathogens. The analogs with selective activity against L. donovani (E4, IC50 0.78 μM), T brucei (E1, IC50 0.12 μM) and T. cruzi (B1- IC50 0.33 μM), and the analogs with broad-spectrum antiparasitic activities against the three kinetoplastid parasites (B1 and B3), may be promising leads for further development as selective or broad-spectrum antiparasitic drugs.
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Affiliation(s)
- Exequiel O J Porta
- Instituto de Química Rosario (IQUIR-CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Suipacha 531, S2002LRK, Rosario, Argentina
| | - María Sol Ballari
- Instituto de Química Rosario (IQUIR-CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Suipacha 531, S2002LRK, Rosario, Argentina
| | - Renzo Carlucci
- Instituto de Química Rosario (IQUIR-CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Suipacha 531, S2002LRK, Rosario, Argentina
| | - Shane Wilkinson
- Queen Mary University of London, Mile End Road, London, E1 4NS, UK
| | - Guoyi Ma
- Department of Infectious Diseases, Division of Scientific Platforms, Southern Research, Birmingham, AL, 35205, USA
| | - Babu L Tekwani
- Department of Infectious Diseases, Division of Scientific Platforms, Southern Research, Birmingham, AL, 35205, USA
| | - Guillermo R Labadie
- Instituto de Química Rosario (IQUIR-CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Suipacha 531, S2002LRK, Rosario, Argentina; Departamento de Química Orgánica, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Suipacha 531, S2002LRK, Rosario, Argentina.
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Nigussie TZ, Zewotir TT, Muluneh EK. Seasonal and spatial variations of malaria transmissions in northwest Ethiopia: Evaluating climate and environmental effects using generalized additive model. Heliyon 2023; 9:e15252. [PMID: 37089331 PMCID: PMC10114238 DOI: 10.1016/j.heliyon.2023.e15252] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Revised: 03/16/2023] [Accepted: 03/31/2023] [Indexed: 04/25/2023] Open
Abstract
The impacts of climate change and environmental predictors on malaria epidemiology remain unclear and not well investigated in the Sub-Sahara African region. This study was aimed to investigate the nonlinear effects of climate and environmental factors on monthly malaria cases in northwest Ethiopia, considering space-time interaction effects. The monthly malaria cases and populations sizes of the 152 districts were obtained from the Amhara public health institute and the central statistical agency of Ethiopia. The climate and environmental data were retrieved from US National Oceanic and Atmospheric Administration. The data were analyzed using a spatiotemporal generalized additive model. The spatial, temporal, and space-time interaction effects had higher contributions in explaining the spatiotemporal distribution of malaria transmissions. Malaria transmission was seasonal, in which a higher number of cases occurred from September to November. The long-term trend of malaria incidence has decreased between 2012 and 2018 and has turned to an increased pattern since 2019. Areas neighborhood to the Abay gorge and Benshangul-Gumuz, South Sudan, and Sudan border have higher spatial effects. Climate and environmental predictors had significant nonlinear effects, in which their effects are not stationary through the ranges of values of variables, and they had a smaller contributions in explaining the variabilities of malaria incidence compared to seasonal, spatial and temporal effects. Effects of climate and environmental predictors were nonlinear and varied across areas, ecology, and landscape of the study sites, which had little contribution to explaining malaria transmission variabilities with an account of space and time dimensions. Hence, exploring and developing an early warning system that predicts the outbreak of malaria transmission would have an essential role in controlling, preventing, and eliminating malaria in areas with lower and higher transmission levels and ultimately lead to the achievement of malaria GTS milestones.
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Affiliation(s)
- Teshager Zerihun Nigussie
- Department of Statistics, College of Science, Bahir Dar University, Bahir Dar, Ethiopia
- Department of Statistics, Faculty of Natural and Computational Sciences, Debre Tabor University, Debre Tabor, Ethiopia
- Corresponding author. Department of Statistics, College of Science, Bahir Dar University, Bahir Dar, Ethiopia.
| | - Temesgen T. Zewotir
- School of Mathematics, Statistics and Computer Science, College of Agriculture Engineering and Science, University of KwaZulu-Natal, Durban, South Africa
| | - Essey Kebede Muluneh
- School of Public Health, College of Medicine and Health Sciences, Bahir Dar University, Bahir Dar, Ethiopia
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James S, Santos M. The Promise and Challenge of Genetic Biocontrol Approaches for Malaria Elimination. Trop Med Infect Dis 2023; 8:201. [PMID: 37104327 PMCID: PMC10140850 DOI: 10.3390/tropicalmed8040201] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Revised: 03/15/2023] [Accepted: 03/23/2023] [Indexed: 04/03/2023] Open
Abstract
Malaria remains an ongoing public health challenge, with over 600,000 deaths in 2021, of which approximately 96% occurred in Africa. Despite concerted efforts, the goal of global malaria elimination has stalled in recent years. This has resulted in widespread calls for new control methods. Genetic biocontrol approaches, including those focused on gene-drive-modified mosquitoes (GDMMs), aim to prevent malaria transmission by either reducing the population size of malaria-transmitting mosquitoes or making the mosquitoes less competent to transmit the malaria parasite. The development of both strategies has advanced considerably in recent years, with successful field trials of several biocontrol methods employing live mosquito products and demonstration of the efficacy of GDMMs in insectary-based studies. Live mosquito biocontrol products aim to achieve area-wide control with characteristics that differ substantially from current insecticide-based vector control methods, resulting in some different considerations for approval and implementation. The successful field application of current biocontrol technologies against other pests provides evidence for the promise of these approaches and insights into the development pathway for new malaria control agents. The status of technical development as well as current thinking on the implementation requirements for genetic biocontrol approaches are reviewed, and remaining challenges for public health application in malaria prevention are discussed.
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Affiliation(s)
- Stephanie James
- Foundation for the National Institutes of Health, North Bethesda, MD 20852, USA
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Biruksew A, Demeke A, Birhanu Z, Kebede E, Golassa L, Mathebula EM, Yewhalaw D. Diagnostic performance of NxTek™ Eliminate Malaria-Pf test for the detection of Plasmodium falciparum in school children with asymptomatic malaria. Malar J 2023; 22:112. [PMID: 36991438 DOI: 10.1186/s12936-023-04529-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Accepted: 03/13/2023] [Indexed: 03/30/2023] Open
Abstract
Abstract
Background
One of the major roadblocks to the falciparum malaria elimination programme is the presence of a portion of the population, such as school children, with asymptomatic malaria infection. Targeting such reservoirs of infections is critical to interrupting transmission and enhancing elimination efforts. The NxTek™ Eliminate Malaria Pf test is a highly sensitive rapid diagnostic test (hsRDT) for the detection of HRP-2. However, knowledge gaps exist in Ethiopia on the diagnostic performance of hsRDT for the detection of Plasmodium falciparum in school children with asymptomatic malaria.
Methods
A school-based cross-sectional study was conducted from September 2021 to January 2022 on 994 healthy school children (aged 6–15 years). Finger-pricked whole blood samples were collected for microscopy, hsRDT, conventional RDT (cRDT or SD Bioline Malaria Ag Pf/P.v), and QuantStudio™ 3 Real—Time PCR system (qPCR). The hsRDT was compared to cRDT and microscopy. qPCR and microscopy were used as reference methods.
Results
The prevalence of Plasmodium falciparum was 1.51%, 2.2%. 2.2% and 4.52%, by microscopy, hsRDT, cRDT and qPCR, respectively. Using qPCR as reference, the sensitivity of hsRDT was higher (48.89%) than the microscopy (33.3%), and showed 100% specificity and a positive predictive value (PPV). Microscopy showed similar specificity and PPV as hsRDT. Using microscopy as a reference, the diagnostic perforrmances of both hsRDT and cRDT were similar. Both RDTs demonstrated identical diagnostic performances in both comparison methods.
Conclusions
hsRDT has the same diagnostic performance as cRDT but improved diagnostic characteristics than microscopy for detection of P. falciparum in school children with asymptomatic malaria. It can be a useful tool for the national malaria elimination plan of Ethiopia.
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Regulatory and policy considerations for the implementation of gene drive-modified mosquitoes to prevent malaria transmission. Transgenic Res 2023; 32:17-32. [PMID: 36920721 PMCID: PMC10102045 DOI: 10.1007/s11248-023-00335-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Accepted: 01/20/2023] [Indexed: 03/16/2023]
Abstract
Gene drive-modified mosquitoes (GDMMs) are being developed as possible new tools to prevent transmission of malaria and other mosquito-borne diseases. To date no GDMMs have yet undergone field testing. This early stage is an opportune time for developers, supporters, and possible users to begin to consider the potential regulatory requirements for eventual implementation of these technologies in national or regional public health programs, especially as some of the practical implications of these requirements may take considerable planning, time and coordination to address. Several currently unresolved regulatory questions pertinent to the implementation of GDMMs are examined, including: how the product will be defined; what the registration/approval process will be for placing new GDMM products on the market; how the potential for transboundary movement of GDMMs can be addressed; and what role might be played by existing multinational bodies and agreements in authorization decisions. Regulation and policies applied for registration of other genetically modified organisms or other living mosquito products are assessed for relevance to the use case of GDMMs to prevent malaria in Africa. Multiple national authorities are likely to be involved in decision-making, according to existing laws in place within each country for certain product classes. Requirements under the Cartagena Protocol on Biodiversity will be considered relevant in most countries, as may existing regulatory frameworks for conventional pesticide, medical, and biocontrol products. Experience suggests that standard regulatory processes, evidence requirements, and liability laws differ from country to country. Regional mechanisms will be useful to address some of the important challenges.
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Assefa A, Wamae KK, Hennelly CM, Ngasala B, Muller M, Kalonji A, Phanzu F, Cunningham CH, Lin JT, Parr JB. Detection of P. malariae using a new rapid isothermal amplification lateral flow assay. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2023:2023.02.26.23286371. [PMID: 37790493 PMCID: PMC10543045 DOI: 10.1101/2023.02.26.23286371] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/05/2023]
Abstract
P. malariae is found worldwide and causes chronic parasitism in its human hosts. We developed a P. malariae (Pm) diagnostic assay that uses rapid, isothermal recombinase polymerase amplification (RPA) and lateral-flow-strip detection. Using 18S rRNA plasmid DNA, the assay demonstrates a detection limit of 10 copies /μL (~1.7 genome equivalents) and 100% analytical specificity. Testing in field samples showed 95% clinical sensitivity and 88% specificity compared to qPCR. Total assay time was 35 minutes. Combined with simplified DNA extraction methods, the assay has potential for future field-deployable point-of-care use to detect a parasite species that remains largely undiagnosed.
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Affiliation(s)
- Ashenafi Assefa
- Ethiopian Public Health Institute, Addis Ababa, Ethiopia
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, NC USA
| | - Kevin K. Wamae
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, NC USA
| | - Chris M. Hennelly
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, NC USA
| | - Billy Ngasala
- Department of Parasitology and Medical Entomology, Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania
| | - Meredith Muller
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, NC USA
| | | | | | - Clark H. Cunningham
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, NC USA
| | - Jessica T. Lin
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, NC USA
| | - Jonathan B. Parr
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, NC USA
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Sun D, Chen Y, Wang L, Hu X, Wu Q, Liu Y, Liu P, Zeng X, Li S, Wang G, Zhang Y. Surveillance and Control of Malaria Vectors in Hainan Province, China from 1950 to 2021: A Retrospective Review. Trop Med Infect Dis 2023; 8:tropicalmed8030131. [PMID: 36977132 PMCID: PMC10051372 DOI: 10.3390/tropicalmed8030131] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Revised: 02/17/2023] [Accepted: 02/18/2023] [Indexed: 02/24/2023] Open
Abstract
Malaria is a serious mosquito-borne tropical disease impacting populations in tropical regions across the world. Malaria was previously hyperendemic in Hainan Province. Due to large-scale anti-malarial intervention, malaria elimination in the province was achieved in 2019. This paper reviews the literature on the ecology, bionomics, and control of malaria vectors in Hainan from 1951 to 2021. We searched PubMed, and the China national knowledge infrastructure (CNKI) database for relevant articles published and included three other important books published in Chinese or English in order to summarize research on species, distribution, vectorial capacity, ecology, the resistance of malaria vectors to insecticides, and malaria vector control in Hainan Province. A total of 239 references were identified, 79 of which met the criteria for inclusion in our review. A total of six references dealt with the salivary gland infection of Anophelines, six with vectorial capacity, 41 with mosquito species and distribution, seven with seasonality, three with blood preference, four with nocturnal activity, two with flight distance, 13 with resistance to insecticides, and 14 with vector control. Only 16 published papers met the criteria of addressing malaria vectors in Hainan over the last 10 years (2012–2021). Anopheles dirus and Anopheles minimus are primary malaria vectors, mainly distributed in the southern and central areas of Hainan. Indoor residual spraying with DDT and the use of ITNs with pyrethroid insecticides were the main interventions taken for malaria control. Previous studies on ecology, bionomics, and resistance of vectors provided scientific evidence for optimizing malaria vector control and contributed to malaria elimination in Hainan Province. We hope our study will contribute to preventing malaria reestablishment caused by imported malaria in Hainan. Research on malaria vectors should be updated to provide scientific evidence for malaria vector control strategies post-elimination as the ecology, bionomics, and resistance of vectors to insecticides may change with changes in the environment.
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Affiliation(s)
- Dingwei Sun
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention (Chinese Center for Tropical Diseases Research), NHC Key Laboratory of Parasite and Vector Biology, WHO Collaborating Center for Tropical Diseases, National Center for International Research on Tropical Diseases, Shanghai 200025, China
- Hainan Provincial Center for Disease Control and Prevention, Haikou 570203, China
| | - Yan Chen
- Hainan Provincial Center for Disease Control and Prevention, Haikou 570203, China
| | - Lu Wang
- Hainan Provincial Center for Disease Control and Prevention, Haikou 570203, China
| | - Ximin Hu
- Hainan Provincial Center for Disease Control and Prevention, Haikou 570203, China
| | - Qun Wu
- Hainan Provincial Center for Disease Control and Prevention, Haikou 570203, China
| | - Ying Liu
- Hainan Provincial Center for Disease Control and Prevention, Haikou 570203, China
| | - Puyu Liu
- Hainan Provincial Center for Disease Control and Prevention, Haikou 570203, China
| | - Xuexia Zeng
- Hainan Provincial Center for Disease Control and Prevention, Haikou 570203, China
| | - Shangan Li
- Hainan Provincial Center for Disease Control and Prevention, Haikou 570203, China
| | - Guangze Wang
- Hainan Provincial Center for Disease Control and Prevention, Haikou 570203, China
| | - Yi Zhang
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention (Chinese Center for Tropical Diseases Research), NHC Key Laboratory of Parasite and Vector Biology, WHO Collaborating Center for Tropical Diseases, National Center for International Research on Tropical Diseases, Shanghai 200025, China
- School of Global Health, Chinese Center for Tropical Diseases Research, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
- Correspondence:
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Echodu DC, Yeka A, Eganyu T, Odude W, Bukenya F, Amoah B, Wanzira H, Colborn K, Elliott RC, Powell SE, Kilama M, Mulebeke R, Nankabirwa J, Giorgi E, Roskosky M, Omoding O, Gonahasa S, Opigo J. Impact of population based indoor residual spraying with and without mass drug administration with dihydroartemisinin-piperaquine on malaria prevalence in a high transmission setting: a quasi-experimental controlled before-and-after trial in northeastern Uganda. BMC Infect Dis 2023; 23:72. [PMID: 36747133 PMCID: PMC9901833 DOI: 10.1186/s12879-023-07991-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Accepted: 01/06/2023] [Indexed: 02/08/2023] Open
Abstract
BACKGROUND Declines in malaria burden in Uganda have slowed. Modelling predicts that indoor residual spraying (IRS) and mass drug administration (MDA), when co-timed, have synergistic impact. This study investigated additional protective impact of population-based MDA on malaria prevalence, if any, when added to IRS, as compared with IRS alone and with standard of care (SOC). METHODS The 32-month quasi-experimental controlled before-and-after trial enrolled an open cohort of residents (46,765 individuals, 1st enumeration and 52,133, 4th enumeration) of Katakwi District in northeastern Uganda. Consented participants were assigned to three arms based on residential subcounty at study start: MDA+IRS, IRS, SOC. IRS with pirimiphos methyl and MDA with dihydroartemisinin- piperaquine were delivered in 4 co-timed campaign-style rounds 8 months apart. The primary endpoint was population prevalence of malaria, estimated by 6 cross-sectional surveys, starting at baseline and preceding each subsequent round. RESULTS Comparing malaria prevalence in MDA+IRS and IRS only arms over all 6 surveys (intention-to-treat analysis), roughly every 6 months post-interventions, a geostatistical model found a significant additional 15.5% (95% confidence interval (CI): [13.7%, 17.5%], Z = 9.6, p = 5e-20) decrease in the adjusted odds ratio (aOR) due to MDA for all ages, a 13.3% reduction in under 5's (95% CI: [10.5%, 16.8%], Z = 4.02, p = 5e-5), and a 10.1% reduction in children 5-15 (95% CI: [8.5%, 11.8%], Z = 4.7, p = 2e-5). All ages residents of the MDA + IRS arm enjoyed an overall 80.1% reduction (95% CI: [80.0%, 83.0%], p = 0.0001) in odds of qPCR confirmed malaria compared with SOC residents. Secondary difference-in-difference analyses comparing surveys at different timepoints to baseline showed aOR (MDA + IRS vs IRS) of qPCR positivity between 0.28 and 0.66 (p < 0.001). Of three serious adverse events, one (nonfatal) was considered related to study medications. Limitations include the initial non-random assignment of study arms, the single large cluster per arm, and the lack of an MDA-only arm, considered to violate equipoise. CONCLUSIONS Despite being assessed at long time points 5-7 months post-round, MDA plus IRS provided significant additional protection from malaria infection over IRS alone. Randomized trials of MDA in large areas undergoing IRS recommended as well as cohort studies of impact on incidence. TRIAL REGISTRATION This trial was retrospectively registered 11/07/2018 with the Pan African Clinical Trials Registry (PACTR201807166695568).
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Affiliation(s)
| | - Adoke Yeka
- grid.11194.3c0000 0004 0620 0548Makerere University College of Health Sciences, School of Public Health, P.O. Box 7072, Kampala, Uganda
| | - Thomas Eganyu
- Pilgrim Africa, Plot 8 Engwau Road, PO Box 577, Soroti, Uganda
| | - Wycliff Odude
- Pilgrim Africa, Plot 8 Engwau Road, PO Box 577, Soroti, Uganda
| | - Fred Bukenya
- Pilgrim Africa, Plot 8 Engwau Road, PO Box 577, Soroti, Uganda
| | - Benjamin Amoah
- grid.7445.20000 0001 2113 8111School of Public Health, Imperial College London, Sir Alexander Fleming Building, South Kensington Campus, London, SW7 2AZ UK
| | | | - Kathryn Colborn
- grid.430503.10000 0001 0703 675XUniversity of Colorado Anschutz Medical Campus, 12631 East 17th Avenue, Aurora, CO 80045 USA
| | - Richard C. Elliott
- Pilgrim Africa, 8001 14th Avenue NE, Suite A, Seattle, WA 98115 USA ,grid.184764.80000 0001 0670 228XMicron School of Materials Science and Engineering, Boise State University, Engineering Building, Suite 338, Boise, ID 83725 USA
| | | | - Maxwell Kilama
- Pilgrim Africa, Plot 8 Engwau Road, PO Box 577, Soroti, Uganda
| | - Ronald Mulebeke
- grid.11194.3c0000 0004 0620 0548Makerere University College of Health Sciences, School of Public Health, P.O. Box 7072, Kampala, Uganda
| | - Joaniter Nankabirwa
- grid.463352.50000 0004 8340 3103Infectious Diseases Research Collaboration, Kampala, Uganda
| | - Emanuele Giorgi
- grid.9835.70000 0000 8190 6402Lancaster University Medical School, Centre for Health Informatics, Computing and Statistics, Lancaster, UK
| | - Mellisa Roskosky
- Pilgrim Africa, 8001 14th Avenue NE, Suite A, Seattle, WA 98115 USA ,grid.21107.350000 0001 2171 9311Johns Hopkins Bloomberg School of Public Health, Baltimore, MD USA
| | - Osborn Omoding
- Pilgrim Africa, Plot 8 Engwau Road, PO Box 577, Soroti, Uganda
| | - Samuel Gonahasa
- grid.463352.50000 0004 8340 3103Infectious Diseases Research Collaboration, Kampala, Uganda
| | - Jimmy Opigo
- grid.415705.2National Malaria Control Division, Ministry of Health Uganda, Kampala, Uganda
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Duguay C, Accrombessi M, N'Tcha LK, Akinro BA, Dangbenon E, Assongba L, Yee SC, Feng C, Labonte R, Krentel A, Protopopoff N, Akogbeto M, Kulkarni MA. Community-level impacts of the coronavirus pandemic on malaria prevention and health-seeking behaviours in rural Benin: A mixed methods study. PLOS GLOBAL PUBLIC HEALTH 2023; 3:e0001881. [PMID: 37205645 DOI: 10.1371/journal.pgph.0001881] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Accepted: 04/06/2023] [Indexed: 05/21/2023]
Abstract
Globally, negative impacts of the COVID-19 pandemic on malaria prevention and control efforts have been caused by delayed distributions of long-lasting insecticidal nets (LLIN), decreased outpatient attendance, and disruptions to malaria testing and treatment. Using a mixed methods approach, we aimed to evaluate the impact of COVID-19 on community-level malaria prevention and health-seeking practices in Benin more than one year after the start of the COVID-19 pandemic. We collected data through community-based cross-sectional surveys with 4200 households and ten focus group discussions (FGDs). Mixed effect logistic regression models accounting for a clustered sampling design were used to identify variables associated with main outcomes (good COVID-19 knowledge, LLIN usage and access, and avoidance of health centres). Consistent with the experiences of FGD participants, receiving information from radios or televisions was significantly associated with good COVID-19 knowledge and avoiding health centres because of the pandemic (p<0.001 for both). Qualitative findings also revealed varying and polarizing changes in health-seeking behaviours with participants noting that they either did not change their health-seeking behaviours or went to health centres less or more often because of the pandemic. LLIN usage and access did not decrease in the study area because of the pandemic (LLIN usage: 88% in 2019 to 99.9% in 2021; LLIN access: 62% in 2019 to 73% in 2021). An unexpected change and unintended challenge for sustained malaria prevention included families socially distancing in their homes, resulting in a shortage of LLINs. Our findings showed that there were minimal community-level impacts of the coronavirus pandemic on malaria prevention and health seeking behaviours in rural Benin, which highlights the importance of efforts to sustain malaria prevention and control interventions in the context of the COVID-19 pandemic.
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Affiliation(s)
- Claudia Duguay
- School of Epidemiology and Public Health, University of Ottawa, Ottawa, Canada
| | - Manfred Accrombessi
- Faculty of Infectious and Tropical Diseases, Disease Control Department, London School of Hygiene and Tropical Medicine, London, United Kingdom
- Centre de Recherche Entomologique de Cotonou, Cotonou, Benin
| | - Ludovic K N'Tcha
- Centre de Recherche Entomologique de Cotonou, Cotonou, Benin
- Laboratory of Applied Anthropology and Education for Sustainable Development, University of Abomey-Calavi, Abomey-Calavi, Benin
| | - Bruno A Akinro
- Centre de Recherche Entomologique de Cotonou, Cotonou, Benin
| | | | - Landry Assongba
- Centre de Recherche Entomologique de Cotonou, Cotonou, Benin
| | - Samantha C Yee
- School of Epidemiology and Public Health, University of Ottawa, Ottawa, Canada
| | - Cindy Feng
- Department of Community Health & Epidemiology, Dalhousie University, Halifax, Canada
| | - Ronald Labonte
- School of Epidemiology and Public Health, University of Ottawa, Ottawa, Canada
| | - Alison Krentel
- School of Epidemiology and Public Health, University of Ottawa, Ottawa, Canada
- Bruyère Research Institute, Ottawa, Ontario, Canada
| | - Natacha Protopopoff
- Faculty of Infectious and Tropical Diseases, Disease Control Department, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Martin Akogbeto
- Centre de Recherche Entomologique de Cotonou, Cotonou, Benin
| | - Manisha A Kulkarni
- School of Epidemiology and Public Health, University of Ottawa, Ottawa, Canada
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The role of chemoprophylaxis in eliminating forest malaria and preventing simian malaria in humans. THE LANCET. INFECTIOUS DISEASES 2023; 23:8-10. [PMID: 36174594 DOI: 10.1016/s1473-3099(22)00519-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Accepted: 07/28/2022] [Indexed: 12/24/2022]
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45
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Potter R, Tesfazghi K, Poyer S, Eliades MJ. Private Sector Contributions to National Malaria Surveillance Systems in Elimination Settings: Lessons Learned from Cambodia, Lao PDR, Myanmar, and Vietnam. Am J Trop Med Hyg 2023; 108:14-23. [PMID: 35914687 PMCID: PMC9904159 DOI: 10.4269/ajtmh.22-0147] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Accepted: 04/29/2022] [Indexed: 02/04/2023] Open
Abstract
Comprehensive malaria case surveillance is necessary to achieve and sustain malaria elimination. In the Greater Mekong Subregion (GMS), the private sector plays a substantial role in malaria treatment. Yet, none of the six GMS countries collects complete case data from private sector points-of-care. Between 2016 and 2019, the GMS Elimination of Malaria through Surveillance program supported national malaria programs in Cambodia, Lao PDR, Myanmar, and Vietnam to execute elimination strategies by engaging the private sector in malaria case management, generating private sector case data, and integrating these data into national surveillance systems. The project enrolled 21,903 private sector outlets, covering between 52% and 80% of the private sector in targeted geographies, which were trained and equipped to perform rapid diagnostic tests (RDTs) and report malaria case data. By 2019, the private providers enrolled in the program reported a total of 3,521,586 suspected cases and 96,400 confirmed malaria cases into national surveillance systems, representing 16% of the total reported caseload by these countries (Cambodia, 25%; Lao PDR, 5%; Myanmar, 12%; Vietnam, 8%). Results demonstrated that with comprehensive support, such as training, provision of free or subsidized RDTs, first-line treatments, and routine supportive supervision, private providers can provide quality malaria case management and achieve high reporting rates.
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Affiliation(s)
| | - Kemi Tesfazghi
- Population Services International, Vientiane, Laos;,Address correspondence to Kemi Tesfazghi, 1120 19th St. NW #600, Washington, DC 20036. E-mail:
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Tavares W, Morais J, Martins JF, Scalsky RJ, Stabler TC, Medeiros MM, Fortes FJ, Arez AP, Silva JC. Malaria in Angola: recent progress, challenges and future opportunities using parasite demography studies. Malar J 2022; 21:396. [PMID: 36577996 PMCID: PMC9795141 DOI: 10.1186/s12936-022-04424-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Accepted: 12/20/2022] [Indexed: 12/29/2022] Open
Abstract
Over the past two decades, a considerable expansion of malaria interventions has occurred at the national level in Angola, together with cross-border initiatives and regional efforts in southern Africa. Currently, Angola aims to consolidate malaria control and to accelerate the transition from control to pre-elimination, along with other country members of the Elimination 8 initiative. However, the tremendous heterogeneity in malaria prevalence among Angolan provinces, as well as internal population movements and migration across borders, represent major challenges for the Angolan National Malaria Control Programme. This review aims to contribute to the understanding of factors underlying the complex malaria situation in Angola and to encourage future research studies on transmission dynamics and population structure of Plasmodium falciparum, important areas to complement host epidemiological information and to help reenergize the goal of malaria elimination in the country.
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Affiliation(s)
- Wilson Tavares
- grid.10772.330000000121511713Global Health and Tropical Medicine, GHTM, Instituto de Higiene E Medicina Tropical, IHMT, Universidade NOVA de Lisboa, UNL, Lisbon, Portugal
| | - Joana Morais
- Instituto Nacional de Investigação Em Saúde, INIS, Luanda, Angola
| | - José F. Martins
- Programa Nacional de Controlo da Malária, PNCM, Luanda, Angola
| | - Ryan J. Scalsky
- grid.411024.20000 0001 2175 4264Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, USA
| | - Thomas C. Stabler
- grid.416786.a0000 0004 0587 0574Department of Medical Parasitology and Infection Biology, Swiss Tropical and Public Health Institute, Basel, Switzerland ,grid.6612.30000 0004 1937 0642University of Basel, Basel, Switzerland
| | - Márcia M. Medeiros
- grid.10772.330000000121511713Global Health and Tropical Medicine, GHTM, Instituto de Higiene E Medicina Tropical, IHMT, Universidade NOVA de Lisboa, UNL, Lisbon, Portugal
| | - Filomeno J. Fortes
- grid.10772.330000000121511713Global Health and Tropical Medicine, GHTM, Instituto de Higiene E Medicina Tropical, IHMT, Universidade NOVA de Lisboa, UNL, Lisbon, Portugal
| | - Ana Paula Arez
- grid.10772.330000000121511713Global Health and Tropical Medicine, GHTM, Instituto de Higiene E Medicina Tropical, IHMT, Universidade NOVA de Lisboa, UNL, Lisbon, Portugal
| | - Joana C. Silva
- grid.411024.20000 0001 2175 4264Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, USA ,grid.411024.20000 0001 2175 4264Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, USA
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Patrick SM, Cox SN, Guidera KE, Simon MJ, Kruger T, Bornman R. COVID-19 and the malaria elimination agenda in Africa: Re-shifting the focus. Glob Public Health 2022; 17:3981-3992. [PMID: 36194811 DOI: 10.1080/17441692.2022.2129729] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The global Coronavirus disease 2019 (COVID-19) pandemic has resulted in public health, political, scientific and private sector response at an unprecedented scale. However, this shift in focus has caused widespread disruption to global health services and has the potential to reverse gains made in efforts to control malaria. If health systems are not able to maintain malaria control interventions while managing the response to the COVID-19 pandemic, malaria cases will increase, thereby placing even more strain on already overtaxed systems. Using a Narrative Review Approach, this commentary explores the impact of COVID-19 on progress made with malaria control and prevention strategies in Africa; and discusses possible mitigation steps to aid community resilience building, through proactive planning and implementation of integrated, inclusive and sustainable strategies to re-shift the focus to attain the malaria elimination goals. We propose strengthening community partnerships, where academia and communities should collaborate and these knowledge-sharing strategies be implemented in order for awareness and interventions to become more networked, inclusive, resilient and effective. Communities should be viewed as 'thought partners', who challenge conventional strategies and aid in developing innovative approaches to community resilience building.
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Affiliation(s)
- Sean M Patrick
- University of Pretoria Institute for Sustainable Malaria Control, School of Health Systems and Public Health, University of Pretoria, Pretoria, South Africa
| | - Sarah N Cox
- Public Health, University of Washington, Seattle, WA, USA.,One Sun Health Inc., New York, USA & Mpumalanga, ZA
| | | | | | - Taneshka Kruger
- University of Pretoria Institute for Sustainable Malaria Control, School of Health Systems and Public Health, University of Pretoria, Pretoria, South Africa
| | - Riana Bornman
- University of Pretoria Institute for Sustainable Malaria Control, School of Health Systems and Public Health, University of Pretoria, Pretoria, South Africa
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Saadeh K, Nantha Kumar N, Fazmin IT, Edling CE, Jeevaratnam K. Anti-malarial drugs: Mechanisms underlying their proarrhythmic effects. Br J Pharmacol 2022; 179:5237-5258. [PMID: 36165125 PMCID: PMC9828855 DOI: 10.1111/bph.15959] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 04/06/2022] [Accepted: 04/28/2022] [Indexed: 01/12/2023] Open
Abstract
Malaria remains the leading cause of parasitic death in the world. Artemisinin resistance is an emerging threat indicating an imminent need for novel combination therapy. Given the key role of mass drug administration, it is pivotal that the safety of anti-malarial drugs is investigated thoroughly prior to widespread use. Cardiotoxicity, most prominently arrhythmic risk, has been a concern for anti-malarial drugs. We clarify the likely underlying mechanisms by which anti-malarial drugs predispose to arrhythmias. These relate to disruption of (1) action potential upstroke due to effects on the sodium currents, (2) action potential repolarisation due to effects on the potassium currents, (3) cellular calcium homeostasis, (4) mitochondrial function and reactive oxygen species production and (5) cardiac fibrosis. Together, these alterations promote arrhythmic triggers and substrates. Understanding these mechanisms is essential to assess the safety of these drugs, stratify patients based on arrhythmic risk and guide future anti-malarial drug development.
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Affiliation(s)
- Khalil Saadeh
- Faculty of Health and Medical SciencesUniversity of SurreyGuildfordUK,School of Clinical Medicine, Addenbrooke's HospitalUniversity of CambridgeCambridgeUK
| | | | - Ibrahim Talal Fazmin
- Faculty of Health and Medical SciencesUniversity of SurreyGuildfordUK,School of Clinical Medicine, Addenbrooke's HospitalUniversity of CambridgeCambridgeUK
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Aldridge R. Is the continued existence of diseases of poverty an indictment of our current humanitarian ethos? BMJ Mil Health 2022; 168:441-443. [PMID: 32152208 DOI: 10.1136/bmjmilitary-2020-001413] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Revised: 02/05/2020] [Accepted: 02/13/2020] [Indexed: 11/04/2022]
Abstract
The continued existence of diseases of poverty is one of the great medical moral dilemmas of the 21st century. That this group of largely either preventable or treatable diseases still plagues a great many of the world's poorest citizens is a challenging problem to address. This paper examines diseases of poverty not by looking at the pathogenic diseases themselves but by looking at the 'diseases' of society that lead to the prevalence of such morbidity. 'Diseases' such as lack of infrastructure, lack of nutrition, lack of education, lack of funding and lack of socioeconomic stability. By addressing each of these, in turn, this paper looks to stimulate thought on how society can approach and prevent diseases of poverty in the future.
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Cohen JM, Kandula D, Smith DL, Le Menach A. How long is the last mile? Evaluating successful malaria elimination trajectories. Malar J 2022; 21:330. [PMID: 36376935 PMCID: PMC9664685 DOI: 10.1186/s12936-022-04368-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Accepted: 11/05/2022] [Indexed: 11/16/2022] Open
Abstract
Background Many national malaria programmes have set goals of eliminating malaria, but realistic timelines for achieving this goal remain unclear. In this investigation, historical data are collated on countries that successfully eliminated malaria to assess how long elimination has taken in the past, and thus to inform feasible timelines for achieving it in the future. Methods Annual malaria case series were sought for 56 successful elimination programmes through a non-systematic review. Up to 40 years of annual case counts were compiled leading up to the first year in which zero locally acquired or indigenous cases were reported. To separate the period over which effective elimination efforts occurred from prior background trends, annual case totals were log transformed, and their slopes evaluated for a breakpoint in linear trend using the segmented package in R. The number of years from the breakpoint to the first year with zero cases and the decline rate over that period were then calculated. Wilcox-Mann-Whitney tests were used to evaluate whether a set of territory characteristics were associated with the timelines and decline rates. Results Case series declining to the first year with zero cases were compiled for 45/56 of the candidate elimination programmes, and statistically significant breakpoints were identified for 42. The median timeline from the breakpoint to the first year with zero local cases was 12 years, over which cases declined at a median rate of 54% per year. Prior to the breakpoint, the median trend was slightly decreasing with median annual decline of < 3%. Timelines to elimination were fastest among territories that lacked land boundaries, had centroids in the Tropics, received low numbers of imported cases, and had elimination certified by the World Health Organization. Conclusion The historical case series assembled here may help countries with aspirations of malaria elimination to set feasible milestones towards this goal. Setting goals for malaria elimination on short timescales may be most appropriate in isolated, low importation settings, such as islands, while other regions aiming to eliminate malaria must consider how to sustainably fund and maintain vital case management and vector control services until zero cases are reached.
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